Reading OI Spurts: Where Open Interest Moved, and How Much

Read the Page in Five Minutes

How do I get to a first reading of the page in about five minutes?

OI Spurts shows which option contracts have just had a fast change in their Open Interest, and which way their price went at the same time. It does not send alerts and it does not rank by percentage. It draws every contract of one expiry on a single chart and leaves the reading to you. This part gets you to a first reading in about five minutes. The page places no order and gives no advice at any step.

1. Open the page

   Open OI Spurts from the rail or the dock (it is labelled OI Spurts). It opens on Top moves for the underlying you have selected, with every strike the expiry lists and the whole day as the window. The rotation map, when you switch to it, opens on 3 strikes: the at-the-money strike and one either side. Pick another underlying in the top bar if you wish; the page follows it.

   Real tool · illustrative dataThe page as it opensSwipe sideways to see all of itEnlarge

   

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2. Read the one-row card

   The row under the page bar names the instrument, gives a verdict (here Bearish · new positions), the contracts Opened and Closed, and a Lean over 5 minutes, 15 minutes and today. It says in words how the contracts that moved lean. It is a rule of thumb, not a forecast (what the words mean).

3. Find the loudest leg in Top moves

   The four cards list every contract whose Open Interest moved, by build-up, loudest first. The first row of a card is the contract that moved the most contracts that way (reading Top moves).

4. Find it on the map

   Press Rotation map. The map places every contract by two moves: how far its premium moved (across) and how far its Open Interest moved (up), each as a percent of what that contract started the window with. The mark carrying a bold path is the loudest leg (or the one you picked), the one that moved the most contracts. The four corners are the four build-ups (the plane). The map opens on 3 strikes around the money, so a loud leg farther out appears only after you widen it in Customise, under Strikes.

5. Open its card

   Rest on a row or a mark (or focus it from the keyboard, or tap it). A small card shows its Open Interest and premium at the window’s start and now (a row’s card, picking a mark).

6. Compare size with speed

   A contract that looks huge on the map because of its percentage often sits low in Top moves, or not at all (Top moves or the map, the trap).

7. Change one thing in Customise

   Customise holds every setting: the window (5m to Day), the number of strikes (each view keeps its own), Calls or Puts, the spurt bar (10, 20 or 30 percent) and how trails are drawn. Try the window 15m to see only the last quarter hour (windows).

What OI Spurts Is

What is OI Spurts, and what will it not do for me?

The page reads one expiry of the option book of one underlying, using the day’s saved snapshots (about one a minute). For each option on the board, a leg, it compares two readings: the one the chosen window opened at, and the latest. It then asks two things: how much did the leg’s Open Interest change, and how much did its premium change. The two answers decide the leg’s place on the map and its build-up.

What the Page Gives You

• Top moves, the view the page opens on: four cards, one per build-up, listing the contracts that moved the most, up or down, with how far each moved against its own book.
• A rotation map in which each leg’s position is its premium move (across) and its Open Interest move (up). The corner it sits in is its build-up.
• An insight card that adds up everything on the board into a verdict, a lean, four checks and the strikes where contracts were written or bought back.
• Time controls: five windows, a chart time you can move back, and a replay of the session.

What It Is Not

Where the code and an older description disagree, this guide follows the page. Figures in the pictures are illustrative: the day was invented to show each part (how the pictures were made).

A

Part A of 7 The screen and its data What am I looking at, and where do its numbers come from? 2 topics

The Screen, Region by Region

What is on the screen, and which part do I read first?

The page has three bands from top to bottom: the page bar, the insight card and the stage, which is either Top moves or the rotation map. A scope line joins them only when you have moved the chart time back. This section names every control and label in them. Controls inside Customise are in the table of every control.

• 1. Page barThe title Open Interest Spurts with an information button, the Stage view switch (Top moves | Rotation map) and the Customise button. When the switch does not fit beside the title it becomes a menu.
• 2. Insight cardOne row: instrument, verdict, Opened, Closed, the Lean over 5m, 15m and today, the scope and the time, and View insight.
• 3. StageOn Top moves, four cards of rows (reading Top moves). On the Rotation map, the plane with four corner words, dashed bar lines and zoom controls, and under it a list of the contracts that moved the most (the plane).
• 4. Replay barUnder the stage, only while Session replay is switched on in Customise (replay).
• 5. Scope lineOnly when the chart time is moved back: expiry, session day, window and number of strikes, as of the time, and Back to latest.

Real tool · illustrative dataThe page bar and the closed insight cardSwipe sideways to see all of itEnlarge

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Reading the Scope Line

When you move the chart time back, a line under the stage tells you exactly what the board covers, so a rewound board can never be mistaken for the latest one. In the pictures it says 6 Oct expiry · On 5 Oct, the whole day · 40 strikes, then as of the time. Three variations matter:

• “as of 11:05” with a Back to latest button: you have moved the chart time back; the board is not the latest.
• “partial day · since 9:40”: the day’s first snapshot came late, so Day measures from then, not from the open.
• A real span in place of a label, such as 25m of 1h: the window reaches back only as far as the session does at that time (windows).

The Marks Name Themselves

There is no separate key under the stage. Each Top moves card names its own build-up, and the rotation map names its four corners and lists its loudest contracts with a circle for a Call and a diamond for a Put. Colour is the direction of the build-up (green for Long Buildup and Short Covering, red for Short Buildup and Long Unwinding) and never means Call or Put (marks and colours).

Where the Numbers Come From, and How Late They Are

Where do the numbers come from, and how often are they read again?

The board is not the live option chain. It is read from the archive of snapshots saved for one trading date and one expiry. That is the reason the page can step back through the session. This section sets out each part of that, in the order a reading travels.

Why This Is Not the Five-Second Chain

The option chain page fetches the whole chain again about every 5 seconds in market hours. OI Spurts does not read that chain for its board. It needs history (a window is two snapshots), and history is what the archive holds. So the board changes about once a minute, and a leg’s Open Interest is only as current as the last saved snapshot. The chain’s premium and this page’s premium are therefore not the same reading.

One Date, One Expiry

The board reads the snapshots of the selected trading date (the latest session by default) and of the expiry chosen under Contract in Customise. Mixing two expiries would put one strike on the chart twice with different histories, so it never does. Changing the underlying or the expiry resets the chart time, the replay and the picked leg; the window and the view stay.

What Is Kept in Your Browser

The view (Top moves or the map), the window and the Customise settings, including a separate strike count for each view, are remembered in this browser, and the strikes you choose are remembered for each underlying. The chart time, a replay and a picked leg are not: reopening the page on yesterday’s 11:05 would draw a stale board that looked current. There are no alerts to keep.

B

Part B of 7 The rotation map How does one chart show every contract’s build-up, and how do I read it? 5 topics

The Plane and Its Four Corners

What do the two axes and the four corners mean?

Every leg on the board is one point on a single chart. Across is how far its premium moved, in percent of the premium it had when the window opened; moving right means the premium rose. Up is how far its Open Interest moved, in percent of the Open Interest it had when the window opened; moving up means contracts were added. The point sits where the two meet. The zero lines cross in the middle.

Real tool · illustrative dataThe rotation map over the whole daySwipe sideways to see all of itEnlarge

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The Corner Is the Build-up

The corner a leg lands in is its build-up. The page does not colour a leg by corner as decoration: the position is the classification. The arithmetic is identical for a Call and a Put. What changes with the side is what the build-up implies for the index.

The last two columns are the page’s own rule for the leg’s lean on the underlying (a Call that is bought, or whose writers buy back, leans bullish; a Put in the same position leans bearish). That is why the colour of a mark follows the corner’s direction and not the side: green means Long Buildup or Short Covering, red means Short Buildup or Long Unwinding, whichever side the leg is on. The lean on the index is taken by the insight card, leg by leg, weighted by contracts (the verdict).

The Corner Words

Each corner of the map carries two lines of writing: a plain phrase on top and the build-up’s name under it (New sellers over Short Buildup, New buyers over Long Buildup, Buyers exiting over Long Unwinding, Sellers exiting over Short Covering). The plain phrase says who is opening or closing positions on the option; it never says bullish or bearish, which is why the lean in the table above is a separate step. Top moves uses the same four phrases (Top moves).

The Axes Say What They Measure

Four small labels name the ends of the two axes: OI (Open Interest) up · contracts added at the top, OI (Open Interest) down · contracts closed at the foot, Price (premium) down · option got cheaper on the left and Price (premium) up · option got dearer on the right (a phone shortens them to OI up added and Price up). Round percentages are printed along both centre lines. They are real percentages, even though the spacing between them is not even: the scale is straight within plus or minus 10 percent and compresses beyond. The chart measures from the start of the window you chose in Customise. On Day that is the first snapshot of the session; on a rolling window such as 15m it is the snapshot 15 minutes earlier, and every mark, and every point of the lead path, is that leg’s move over the 15 minutes ending at its time.

Marks: Colour, Shape and Size

What do a mark’s colour, shape and size tell me?

A mark carries four facts: where it sits (two percentages), what colour it is (the direction of its build-up), what shape it is (its side) and how big it is (how much Open Interest the leg holds). Learn the four once and every picture of the page reads the same way.

Labels

The map prints a name beside a mark (“23300 Call”) only where it fits, and never on a phone, so the chart does not turn into a wall of text. Under the plane a list names the 8 contracts that moved the most Open Interest, each with its plain phrase and its two percentages; resting on a row lights its mark, and the line “and N more” sends you to Top moves, which lists every one (Top moves). Every mark has a full reading for a screen reader (“23300 Call · short buildup · +71.3% Open Interest, -25.4% premium. Select”), and resting on a mark shows it.

Flat Marks Are Not Spikes

A leg that started the window with 5000 contracts or fewer is drawn on the zero line of the Open Interest axis whatever it did, and has no build-up. A premium of ₹0.05 or less at the start does the same on the premium axis. The page does this on purpose: otherwise one leg with a handful of contracts would stretch the whole chart and drag every trail out to chase it. The contracts it moved still count in Opened and Closed in the insight card; they are only kept out of the lean.

No Clamp: the Frame Fits the Board

A percentage is never cut off. The map fits its frame to the bulk of the board (97 percent of the contracts, and of the lead path), rounded up to a round percentage, and draws both axes on a scale that is straight within plus or minus 10 percent and compresses beyond, so a leg at plus 900 and a leg at plus 12 share one chart. The few loudest legs beyond the frame ride the rim of the chart, and the small card still prints their real figure: the frame is a view, never a limit on the number. In the pictures the 22750 Put reads +241.7%.

Marks Past the Edge

When you zoom in, a mark outside the view is drawn as a small, faint dot riding the edge of the chart, so a zoomed view still shows that the leg exists. Only the lead leg and the picked leg keep their full mark, with a small arrow at the edge. Press the reset button to fit the view to the board again.

Trails: How a Leg Got There

How did a leg get to where it is?

A mark shows where a leg is now. A trail shows the path it walked to get there, on the same two axes. Each point on the path is that leg read over the same window, ending a little earlier. The map’s premise is trajectory: a leg that walked from Long Unwinding into Long Buildup at about 11:40 tells you more than its place at 2:20.

Which Trails Are Drawn

Two settings in the Paths section of Customise answer two different questions. Path (Off or On; the page opens on On) says whether paths are drawn at all, from the centre at the moment the window opened to now. Show says which legs get a path: Lead only (the pick, else the loudest leg; the default), Big moves (every leg over the spurt bar, and the pick) or All. At most 60 paths are drawn. On a board of one or two strikes, every leg keeps its path whatever the setting, because four legs cannot tangle.

The Lead Path and Its Start Time

One path carries the story: the picked leg, or the loudest leg when nothing is picked. It is drawn bold, from a small dot at the centre, with the clock time it began beside the dot (“9:15 am” on the whole day) and an arrowhead into the leg’s mark. Only this path has a start time. The other paths, when you ask for them, are faint context. The path bends where the leg changed direction, so you can follow it across corners; the insight card says in words what it did (the verdict).

A Rotation Is a Change of Corner

When the bold path leaves one corner and settles in another, the insight card’s detail says so in words and gives a time (“The … rotated out of … into … around …, and has held there since”). The page treats the time as observed only when the archive has no hole between the two readings; across a gap the path is drawn broken and no rotation time is claimed.

One Strike, Both Legs

The cleanest way to read a trail is to choose a single strike (Choose strikes). Both its Call and its Put then keep a path, and you can see whether they moved together.

Real tool · illustrative dataA board of one strikeSwipe sideways to see all of itEnlarge

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Picking a Mark: the Card

What does a picked mark tell me, and which figures can I check?

Select a mark (or a row of the list under the plane) with a click or a tap, or focus it with the keyboard and press Enter or Space. The pick adds one thing to the whole page: it becomes the lead leg, so its path is the bold one. Select it again to clear the pick. Escape closes its small card.

The Small Card

Resting the pointer on a mark or a list row, focusing it, or tapping it opens one small card. It names the leg and its build-up (the plain phrase first, for example New sellers · Short Buildup), then gives two lines: Open Interest and Premium, each as the figure when the window opened, an arrow, the figure now and the change in percent. On the map a third line, Size, says how the leg’s book compares with the biggest book on the map. The foot line says whether the strike is at, in or out of the money and, for a big move, a big move: 20% or more of its own Open Interest (the figure is the bar you set). The two percentages are the leg’s own coordinates on the map: for the 23300 Call in the pictures, +71.3 percent up and −25.4 percent across.

The Same Card on Top Moves

The card is not special to the map. A row of Top moves opens the same card when the mouse rests on it, when it takes focus, or when you tap it, so a contract reads the same in both views (a row’s card).

A Leg That Was Not Measured

A leg that is listed now but was not listed when the window opened (a strike added to the ladder during the day) has no comparison. It has no mark on the map and no row in Top moves, never a zero, and it is left out of every total.

Zooming the Map

How do I zoom, move and use the map from the keyboard?

Most of the marks crowd near the zero line, so the map can be zoomed. The zoom is about the centre, where every path starts, and the percentages on the axes stay real at every level. The page keeps your zoom when a new snapshot arrives.

Real tool · illustrative dataThe map controlsEnlarge

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Each mark is a button of its own, so the keyboard reaches every one with Tab; Enter or Space picks it. There is no drag, wheel or arrow-key panning: the buttons are the whole camera.

Real tool · illustrative dataThe map zoomed inSwipe sideways to see all of itEnlarge

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Reading Top Moves

How do I read Top moves, and what does the order of its rows mean?

The page opens on Top moves, the first of its two views (the other is the Rotation map, Part B). It says in words what the map draws. Every contract whose Open Interest moved over the window is listed, sorted into the four ways a move can happen, loudest first, in four cards. There is no chart to decode: a row is a contract, how many contracts it moved, and how its price went at the same time.

Real tool · illustrative dataTop moves for NIFTY since 9:15Swipe sideways to see all of itEnlarge

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Four Cards in the Map’s Own Corners

The four cards sit where the map’s four corners sit, so Top moves is also the easiest way to learn the map. On a wide screen the cards are two by two; on a phone they stack one under the other in the same order.

Premium fell on the left and rose on the right; positions were added in the top row and closed in the bottom row. The plain phrases describe who is opening or closing positions on the option. They never say bullish or bearish; the lean on the index is the insight card’s job (the verdict). Colour follows the same rule as the map: green for Long Buildup and Short Covering, red for Short Buildup and Long Unwinding.

What Each Card Shows

On the guide’s invented day, measured since 9:15, the 23300 Call is the loudest contract of the Short Buildup card: its row reads +70.64L contracts, +71.3% of its own book and −25.4% on the premium. Those are the same three numbers its mark shows on the map.

Sorted by Contracts, Not by Percent

Rows are ordered by the number of contracts moved, up or down, largest first. That is deliberate: the percentage is a speed against the leg’s own book, and a small book can show a large percentage with very few contracts (the low-base trap). Top moves answers which contracts moved the most; the map answers how fast, against their own books. The percentage column is there so you can still see both on one line.

The Rail: How Big Is the Move Against the Book

The bar in each row is the Option Chain’s own Open Interest bar, drawn for one contract. All four cards share one scale, so a bar means the same length in every card. A solid segment is the Open Interest that stayed. Where contracts were added the move is hatched; where contracts were closed it is a pale wash with a thin edge standing at today’s level. A long hatched bar on a short solid one is a big build on a small book; a short hatched bar on a long solid one is a small step on a large book.

What Top Moves Leaves Out

• Legs with no build-up. A leg that opened the window with 5000 contracts or fewer, or whose premium did not move, has no build-up and no card to sit in (the floors). Their contracts still count in Opened and Closed on the insight card.
• Legs that did not change. A leg whose Open Interest is the same as at the window’s start is not listed.
• Legs not measured. A leg that was not listed when the window opened has no comparison and no row.
• The key and the scope line. Top moves draws neither: each card names its own marks, and the expiry, window and strikes are Customise’s. When you have moved the chart time back, a scope line does appear, with Back to latest, so a rewound board never passes for the live one.

A Row and Its Small Card

How do I open a row’s figures?

A row cannot print everything, so each one opens one small card. Rest the mouse on a row for about a tenth of a second (120 milliseconds), focus it with the keyboard, or tap it on a touch screen. A second tap, Escape, a scroll or a resize closes it. Only one card is open at a time, and it never opens the page’s big panel.

Real tool · illustrative dataResting on a rowSwipe sideways to see all of itEnlarge

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The same card opens from a mark or a list row on the rotation map; there it adds one line, the leg’s book as a share of the biggest book on the map. Moneyness is worked out from the board’s at-the-money strike: a strike equal to it is At the money; a Call is In the money below the price and out of the money above it, and a Put is the reverse. The card prints it because a build far out of the money has a different meaning from one at the money (near and far).

Using the Keyboard

Each row is a button. Tab walks the rows in card order and opens each one’s card as it takes focus; Escape closes it. Every row also carries a full reading for a screen reader, such as 23300 Call: Short Buildup, Open Interest +70.64L (+71.3% of its own), premium −25.4%, a big move of 20% or more.

Top Moves or the Map: Which When

Should I use Top moves or the rotation map?

The two views read the same archive, the same window, the same legs and the same spurt bar. The strikes differ unless you change them: Top moves opens on every strike the expiry lists, and the rotation map on 3 (the at-the-money strike and one either side). Neither view is the better one. They answer two different questions, and a careful reading uses both, in an order.

A good habit is the pair: read the four cards first, then press Rotation map and find the same contract on the plane. The switch is remembered in this browser, so the page reopens on the view you left; the first time it opens on Top moves. Each view also remembers its own strike count, and a count you pick in Customise applies to the view that is open. The Customise panel adapts: the Paths section appears only on the map.

D

Part D of 7 Customise, every control How do I change the window, the legs, the bar, the paths and the time? 5 topics

Windows: Measured Over How Long

Over how long is every percentage measured?

Customise opens with Contract (the expiry) and then Time. The first choice in Time is the window: 5m, 15m, 30m, 1h or Day. It decides which two snapshots every percentage on the page compares. Change nothing else and the board already looks different, because a move over the whole day and a move over the last quarter hour are different questions.

Real tool · illustrative dataCustomise: the Time sectionEnlarge

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How the Page Finds the Start

A window is not a clock. The page works out how many snapshots back the label reaches from the archive’s own spacing (its median gap), takes that snapshot, and then checks that the snapshot is really about as far back as the label promises. The tolerance is 2.5 minutes. That check is why the page never prints a two-hour move under a “15m” heading after a gap in the archive. Three outcomes follow:

• It fits. The hint reads Since 12:30. This is the normal case.
• It reaches back only to the open. At 9:45 with 1h chosen, the window can start no earlier than 9:15. The page keeps the reading and prints its real length: 30m of 1h · since 9:15. The option is greyed in Customise at that moment, but a greyed option can still be the checked one.
• The nearest start is too old. After a hole in the archive the nearest snapshot may be far older than the label. The page then says “No snapshot sits close enough to the 15m boundary — the nearest one is 127 minutes back, so this window is not measured rather than silently widened”, and the verdict reads Window not measured.

Real tool · illustrative dataThe same board over the last 15 minutesSwipe sideways to see all of itEnlarge

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Day Means Two Different Things

On Top moves and the map, Day is measured from the first snapshot of the session (9:15 in the pictures). The insight card’s own Day choice is measured from the previous session’s close when that close is held, and says so (“since the 1 Oct close”). A caveat in the card reminds you of this. They are not a mistake; they are two baselines. The close-based figure includes the overnight and any gap at the open (the insight card).

The Insight Card Has Its Own Capsule

Inside the opened card, Measured over offers 5 min, 15 min and Day. It sets the page window to the same value. For the page’s 30m and 1h windows the card reads the board’s own window and says so (“30 min board, set in Customise”).

Strikes, Legs and the Spurt Bar

Which legs are on the board, and where does the spurt bar sit?

The Board section of Customise decides which legs are on the chart and where the bar sits. It has three controls, in this order: Strikes, Legs and Big move ≥, which sets the spurt bar.

Real tool · illustrative dataCustomise: the Board sectionEnlarge

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Strikes: Nearest

The capsule offers 1, 3, 5, 11, 15, 21, 29 and All. A count is the number of strikes nearest the at-the-money strike at the time shown; both the Call and the Put of each are on the board, so 21 strikes is up to 42 legs. The two views open on different counts, on a desktop and on a phone alike: Top moves (the table) on All (every strike the expiry lists), and the rotation map (the chart) on 3, the at-the-money strike and one either side. Each view remembers its own count, and the count you pick here applies to the view that is open, so widening the map leaves Top moves as it was. The pictures in this guide were taken with All on both views, which is 40 strikes and 80 legs on this expiry, before the map’s opening count changed to 3 (pictures not retaken). When you widen the map, its scale is built for it: far strikes move hundreds of percent and the money moves tens, and the scale keeps both readable. A larger stop is greyed once a smaller one already shows every strike the expiry lists. The last stop, All, reads every strike. 1 and 3 still follow the money as it moves.

Strikes: Choose Strikes

Press Choose and the capsule changes to a grid of every strike the expiry lists, the at-the-money one marked ATM and the grid opened on it. Tap the strikes you want. The footer says 3 of 40 strikes (in the picture) and has a Clear button. Your set is kept for each underlying separately (a NIFTY ladder means nothing on BANKNIFTY), does not re-centre as price moves, and is not undone by Reset. When you switch Choose on with nothing chosen, the page starts you from the at-the-money strike. If none of your strikes is listed in the expiry, the stage says so and tells you where to choose others; nothing is borrowed from a neighbour.

Real tool · illustrative dataChoose strikesEnlarge

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Legs

Calls and puts (the default) reads both legs of every strike. Calls or Puts reads one side, and the scope line adds “calls only” or “puts only”. A reader who follows the Call side of a strike does not have to read round the Puts to find it. The insight card then reads the same board.

The Spurt Bar (Big Move ≥)

The control is labelled Big move ≥; the number it sets is the spurt bar. It is the one spurt setting: 10, 20 or 30 percent of a leg’s own Open Interest, and 20 when the page opens. It is stored in this browser, and a stored value that is not one of the three is ignored. The bar does not hide or add any leg. It does four things only:

• draws the two dashed lines on the map and marks the rows of Top moves that are big moves;
• counts the legs over it (the map’s screen-reader label says “80 contracts, 8 with a big move of 20% or more”, and the insight’s detail lists Legs over the spurt bar, 8 of 80);
• decides which paths are drawn when Show is Big moves;
• feeds one of the four checks behind the verdict (at least 3 legs over the bar).

Real tool · illustrative dataSpurt bar 10 percentSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataSpurt bar 30 percentSwipe sideways to see all of itEnlarge

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On the same board the count is 9 at 10 percent, 8 at 20 and 7 at 30: here the day’s moves are either small or large, so the bar changes little. On a board where many legs sit between 10 and 30 percent it changes a great deal. Notice what is not a setting: there is no minimum size and no minimum starting book you can set. One fixed floor of 5000 contracts is built in (the low-base trap). To insist on a minimum size, read Top moves, which ranks by contracts.

The Same Page on Another Underlying

The page follows the underlying selected in the top bar. In the pictures a stock has a larger lot and a thinner book, so the same percentage is carried by far fewer contracts.

Real tool · illustrative dataBANKNIFTYSwipe sideways to see all of itEnlarge

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Real tool · illustrative dataRELIANCE (a stock)Swipe sideways to see all of itEnlarge

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Paths on the Rotation Map

How are paths drawn on the map?

The last section of Customise, Paths, appears only while the rotation map is the stage view. Top moves draws no paths, so it hides these settings. A path starts at the centre when the window opened and runs to where the leg is now.

Every leg on a wide board means up to 60 paths; the widest count, 29 strikes (58 legs), still fits. The default, one lead path, keeps a busy day readable. Set Show to All when you want to see how the whole board travelled, and choose a shorter window so the picture is not a tangle.

Chart Time and Session Replay

How do I see the board as it was earlier, or play the session back?

The board is drawn at the newest snapshot unless you move it. Chart time, in the Time section of Customise, takes it back to an earlier snapshot; Session replay plays the board forward from there, one snapshot at a time. Both exist to answer “what did this look like when I was not watching?”, and both are deliberately forgotten when you leave: an old board must never pass for the current one.

Chart Time

• The stepper shows the time of the snapshot (“2:20”) and a tag Latest when you are at the newest. The arrows are Previous snapshot and Next snapshot.
• The slider (“Chart as of market time”) runs from the first snapshot to the last, with their clock times under its ends.
• The hint says how far behind you are (“The newest snapshot”, or how long before the newest the chosen one is).
• Back to latest returns to the newest and lets the board follow new snapshots again. The scope line shows the same button while you are away.

Real tool · illustrative dataChart time moved back to 11:05Enlarge

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The Replay Bar

Switch Session replay on and a bar opens under the chart. It always opens closed: a replay is a moment, not a preference.

Real tool · illustrative dataThe replay barSwipe sideways to see all of itEnlarge

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Playback stops by itself at the last snapshot and when the tab goes into the background. While it plays, the map’s camera is held still so the picture does not jump.

Real tool · illustrative dataThe board rewound to 11:05Swipe sideways to see all of itEnlarge

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The First Snapshot: Nothing Behind It

Move the chart time to the very first snapshot and the page has nothing earlier to compare with. It does not say the archive is short; it says where you are: This is the session’s first snapshot, so there is nothing behind it to measure a window against. Go back to the latest snapshot, or move the chart time forward in Customise, and the board fills in. The insight card above it, whose Day is measured from the previous close, can still give a reading (with 5m and 15m leans shown as a dash); the card says At the open only when the window it reads has no start. Step forward one snapshot and the board returns.

Real tool · illustrative dataParked on the first snapshotSwipe sideways to see all of itEnlarge

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Every Control: Default, Choices and What Is Kept

What is every control, its default, and what does the browser keep?

One table for the whole Customise panel, in the order the panel shows it. Every change applies at once; the panel has only Reset and Close. Escape closes it and returns focus to the Customise button.

Real tool · illustrative dataThe whole Customise panel (drawn at full length)Enlarge

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Reset

Reset puts the page back as it opens: strikes to All on Top moves and 3 on the rotation map, Calls and puts, bar 20, Path On, Show Lead only, the window to Day, the board on the newest snapshot and the replay closed. It keeps the strikes you chose (they are a list you built, not a setting) and the expiry (the contract you are reading, not a preference).

Storage

Settings live in this browser’s own storage. If the browser blocks storage (a private window, for instance) the page still works and the choices last for that visit. Nothing is sent to a server.

E

Part E of 7 The insight card What does the card say, and how is the verdict decided? 3 topics

The Insight Card, Closed and Open

What does the card above the chart tell me?

Above the stage sits a card that adds up the whole board for you. It reads the strikes of Top moves (every strike unless you pick a count while Top moves is open) and the legs you set, whichever view is open, so it spares you the arithmetic. On the rotation map, which opens on 3 strikes, the card can therefore cover more strikes than the chart draws. Its Day baseline also differs from the map’s (windows), so its figures can differ a little. Closed, it is one row. Open, it gives a verdict, the reasoning, three reading lines and a detail panel in which every figure shows its formula.

The Closed Row

• The verdict pill, such as Bearish · new positions (all the words).
• Opened and Closed: the contracts added on the legs whose Open Interest rose, and removed on the legs whose Open Interest fell (“1.85Cr”, “60.91L”; a crore is a hundred lakh).
• Lean over 5m, 15m and Today: the share of the size that moved with a direction that leans bullish or bearish, in each of three windows. When too little moved it prints quiet or no lean.
• The scope (“40 strikes · since the 1 Oct close”) and the time of the reading.
• View insight to open it.

The Open Card

Real tool · illustrative dataThe insight card, openedSwipe sideways to see all of itEnlarge

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Two Standing Notes

Every card ends its caveats with two sentences that do not change: Build-up names are conventional readings of premium and Open Interest together; a hedge or a roll prints the same way, and Traded volume is not collected in this archive, so no check asks whether the tape agrees. Read both before you rely on any verdict. They are the page being honest about what it cannot see.

Lean in Three Windows

The three Lean figures read the same board over 5 minutes, 15 minutes and today. They can differ, and the difference is information: a day that leaned one way and a last quarter hour that leans the other is a changing book. They are on the same lean lines (green at 60 percent bullish or more, red at 40 or less, grey between), and a window with too little movement says quiet instead of a number. Five- and fifteen-minute lean figures need a snapshot that far back, within 1.5 and 2.5 minutes; when none sits that close the page says the window is not measured.

The Verdict: Every Word and the Rule Behind It

How is the verdict decided, and what does each word mean?

The verdict is the answer to two questions asked in order. First: are positions being opened or closed? That is regime. Second: of the size that moved with a direction, which way does it lean? That is the lean. Four checks then say how firmly the board backs it; they never change the verdict.

Question One: Opened or Closed

The page adds up the contracts opened (Open Interest rose) and closed (it fell), and works out net as the difference divided by the two added together, printed to one decimal place:

Before that, a floor: a window in which fewer than 20 lots changed (or 0.05 percent of the Open Interest standing on the strikes read, if that is larger) is Quiet, and no direction is read. The floor is counted in lots of the instrument’s own lot size, so NIFTY’s 65 and a large-lot stock are not held to one absolute count.

Question Two: the Lean

Every leg that moved on both Open Interest and premium has a direction: by its build-up and its side it leans bullish or bearish for the underlying (the table of corners). The lean is the bullish size divided by the bullish plus the bearish size, with every leg weighted by the contracts it moved, never counted. At 60 percent bullish or more the lean is bullish; at 40 or less, bearish; between, no lean. A lean prints only if at least 25 percent of the turnover carried a direction; otherwise the page says so (No clear direction) rather than present the lean of a sliver as the lean of the board.

The Words

The colour follows the lean: green for bullish, red for bearish, grey for neither. Notice Bullish · positions closing is green: it describes bearish positions coming off, which leans bullish. Read the words, not only the colour.

The Four Checks, the Levels and the Detail Panel

How firmly does the board back the verdict, and where are the levels?

Behind every verdict are four scored checks, one point each. They say how firmly the board backs the verdict. They never change it. A fifth check, whether the traded volume agrees, is skipped and never counted, because volume is not collected here; the page shows it as a note, not a failure.

Three or four passes read as firm, two as partial, fewer as thin. The card also names the strongest thing arguing against its own verdict (“The loudest leg argues back…”), because one heavy leg against the board does not settle which reading is right.

The Detail Panel

The button Full detail and calculations opens a panel in which every figure printed above has its formula and this reading’s own numbers. It has six parts: How the verdict is decided, Flow and lean, Biggest movers, Levels, 5 min, 15 min and Today and Data and scope. Each step shows a tick, a cross or a dash, so the verdict is an argument you can inspect.

Real tool · illustrative dataThe detail panelSwipe sideways to see all of itEnlarge

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Biggest Movers

The movers table lists up to eight legs by contracts moved, with the build-up, Open Interest then and now, the change in contracts and percent, the premium percent, the lean and the Share of everything that moved. A leg with a thin start prints thin start in place of a percentage, so you can see which headline percentages the page refuses to trust.

Real tool · illustrative dataBiggest moversSwipe sideways to see all of itEnlarge

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The Levels

The levels are this window’s writing and buying back, not the standing book. The possible ceiling is the Call at or above price with the most contracts written (Short Buildup) in the window. The possible floor is the Put at or below price with the most written. A level coming off is the louder of the Call at or above price or the Put at or below it with the most contracts bought back (Short Covering). A Put above price or a Call below it is never a level: the market is already past it.

Real tool · illustrative dataThe levelsSwipe sideways to see all of itEnlarge

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F

Part F of 7 Traps, examples and routines When is a spurt worth reading, and how do I read one in order? 5 topics

The Low-Base Trap: A Big Percentage of Almost Nothing

When is a big percentage not worth reading?

A percentage of a leg’s own book has one weakness: when the book is tiny, a handful of contracts is a large percentage. A far-away strike that holds a few thousand contracts can print a bigger percentage than any busy strike on the board and mean nothing at all. This is the most important section of the guide for anyone who reads spurts, because the percentage is exactly what makes the map useful and exactly what makes it misleading.

What the Page Already Does About It

The floors are fixed. You cannot raise them, and no other minimum can be set. They remove the extreme cases and nothing more. A leg that opens with 5001 contracts is measured, and a percentage of that is just as thin in spirit.

Both Sides of the Trap in One Picture

The pictures use a board of three strikes chosen to show it: 22750, 23300 and 23700. The 23700 Call opened with 4290 contracts, which is 5000 contracts or fewer. The 22750 Put opened with 6240, just over it.

Real tool · illustrative dataThree strikes on the rotation mapSwipe sideways to see all of itEnlarge

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The numbers on a contract’s card are the whole argument. The 22750 Put added 15.1K contracts, a rise of +241.7%, on a premium of ₹0.10 falling to ₹0.05. The 23300 Call added 70.64L contracts, a rise of +71.3%. In contracts the Call moved about 470 times as many. A reader who sorted by percentage would put the Put first and the Call a long way down.

How to Read Around It

1. Size first, percentage second

   Open Top moves. If the leg that stands out on the map sits at the foot of its card, or is only counted in “and N smaller”, stop. If it is one of the first rows, the percentage then tells you how fast it arrived.

2. Look at the starting book

   On a contract’s card, read the first Open Interest figure, the book when the window opened. A start of a few thousand contracts is thin whatever the percentage says; compare it with the biggest legs on the board.

3. Look at the distance

   A leg far from the money is rarely part of this session’s positioning (next section).

4. Trust the grey marks

   When the page refuses to name a build-up, do not name one for it.

Size, Distance, Premium and Who Traded

What else can mislead me even when no leg is thin?

Four more reading errors are common even when nothing is thin. Each has a check on the page.

1. Contracts, Not Percent, for Size

A move of 70.64L contracts is a large share of the board. A move of 15.1K is a sliver of it. Top moves, which sorts its rows by contracts moved, is the view that ranks by contracts. The percentage and the rank can disagree; when they do, the rank is about size and the percentage is about speed.

2. Distance From the Money

A build near the at-the-money strike is in the contracts closest to price. A build far away sits in contracts that are usually cheaper and thinner, which is a reason to check its size before reading it as today’s positioning. The card says At the money, In the money or Out of the money, and the at-the-money strike is ringed in Top moves. A simple habit: compare the big row’s strike with the ringed one before you give it a meaning.

3. Premium Moves With the Index

Both axes of the map are measured on the option as it is. The premium axis therefore includes whatever the index itself did. Consider a Call near the money while the index rises 60 points: its premium rises whether or not anyone bought it. A Short Covering label (Open Interest down, premium up) on that Call may be only a price rise that happened while shorts also closed. The page does not remove the index’s share. Before you name a build-up, ask what the index did over the same window: the scope line gives the window and the top bar the index.

4. Open Interest Cannot Say Who

Every contract has a buyer and a seller. Rising Open Interest says new positions were opened; it does not say whether the buyer or the writer was the more eager. The premium’s direction is a hint, and the page calls the names conventional readings. Two ordinary things also print as builds: a hedge (a position held against another, for example Puts bought against shares) and a roll (a position moved to another strike or expiry, which shows as Open Interest falling on one leg and rising on another). The page cannot tell either from a new view, and it collects no volume to help.

Four Worked Examples (Illustrative)

What does a reading look like with real figures, in order?

Each example uses the pictures’ invented day: NIFTY on 5 October 2026 at 2:20 pm, expiry 6 October, window Day unless stated, with every strike on the board (the pictures were taken before the map’s opening count changed to 3 strikes). The figures are what the page printed in those pictures. They are not market quotes and nothing in them happened. The point of each is the order of reading.

Routines: Expiry Day, a Positional View and a Review

What should I do on expiry day, for a positional view and after the close?

Three routines that use only what the page does. None of them gives a trade. They are orders of reading.

On Expiry Day

Near expiry, option premiums can shrink to a few rupees, so a one-rupee move can be a very large percentage and the premium axis stretches. The map is at its most extreme and its percentages are at their least reliable. The routine:

1. Open the 5m or 15m window

   The Day window is dominated by the morning. Set the window to the last 5 or 15 minutes (windows).

2. Narrow the strikes

   The rotation map already opens on 3 strikes; on Top moves, pick 1 or 3 while it is open, or choose one or two strikes, so the board is small (on a board of one or two strikes every leg keeps its path). Wide boards on expiry day are mostly cheap legs (strikes).

3. Rank by contracts

   Use Top moves. A leg whose premium opened at ₹0.05 or less reads flat on the premium axis by design, so the map draws it without a build-up and Top moves leaves it out; its contracts still count in Opened and Closed on the insight card.

4. Read the card against the index

   On this day premiums are small and tend to follow the index closely. Name no build-up before you have looked at what the index did over the window (premium moves with the index).

5. Mind the age of the reading

   The board is read from saved snapshots about a minute apart. In the last hour of expiry day a minute matters; the insight card’s time stamp says which reading you are on.

The settle time and expiry rules are the exchange’s. This guide does not state them (not verified).

For a Positional View

The page reads one trading date. It cannot draw several days at once, so for a view of days use it as a daily check:

1. Choose the expiry you hold

   Set the expiry under Contract to the series you trade, not the nearest.

2. Read Day against the previous close

   Open the insight and keep Day. It is measured from the previous close, which is the figure that includes the overnight.

3. Look for the same strikes on consecutive days

   Note the loudest legs of the day and compare them with your note of yesterday’s. For the standing book across days use the Open Interest page.

For a Review After the Close

1. Replay the session

   Switch on Session replay, press play at 4x and watch which legs appear and where they rotate (replay).

2. Pause on each rotation

   When a bold path changes corner, pause and read the tag with its time.

3. Write down what price did

   The page does not keep alerts. If you want to know what a spurt was worth, note what the index did afterwards in your own notes.

Mistakes and a Checklist

What do readers get wrong, and what should I check before I give a spurt a meaning?

The mistakes below come from the way the page is built, not from carelessness. Each has the section that cures it.

A Checklist Before You Give a Spurt a Meaning

• Is it one of the first rows in Top moves, or far down its card?
• Did it start with more than a few thousand contracts?
• Is its strike near the at-the-money strike?
• What did the index do over the same window?
• How many of the last three steps agree?
• Do the neighbouring strikes show the same side building?
• Does the shorter window agree with the longer one?
• Is the board at the newest snapshot (no as of time and no Back to latest button)?

If you cannot answer one of these, the page has probably told you where to find it: the card or the scope line.

G

Part G of 7 Phone, states and limits How do I use it on a phone, what do its messages mean, and where are its limits? 4 topics

Using It on a Phone

How do I use the page, and this guide, on a phone?

At 768 pixels wide or narrower the page switches to its phone layout. Nothing is removed from the analysis; controls move to where a thumb reaches them. The pictures below were taken in a phone-sized browser window (390 pixels wide) with touch on.

Real tool · illustrative dataThe page on a phoneEnlarge

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Real tool · illustrative dataTop moves on a phoneEnlarge

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What Changes

Real tool · illustrative dataThe insight, as a sheetEnlarge

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Reading This Guide on a Phone

A picture wider than the screen scrolls sideways inside its frame and says so (“Swipe sideways to see all of it”). The Enlarge button opens the full-size picture in a panel; Close or a tap outside dismisses it. A table that is wider than the screen scrolls sideways in the same way, and can be reached with the keyboard. The contents list is under the Sections button at the foot of the page.

The phone pictures are from an emulated screen, not a real phone: not verified on devices.

What the Page Says When There Is Nothing to Draw

What does the page say when it has nothing to draw?

The page is built to say why it has nothing, and to never print a zero in place of a missing reading. Each message below is the page’s own.

Real tool · illustrative dataWhen the feed cannot be readSwipe sideways to see all of itEnlarge

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Which Tool When

When do I use OI Spurts and when another tool?

OI Spurts answers one question: what has just changed in the option book, and in what size. The other tools answer the questions around it.

A common order: find the standing walls on the Open Interest page, then use OI Spurts to see whether the day is building or removing them.

What the Page Does Not Do

What does the page not do?

A short list, and each item is a thing readers have expected of it.

• It sends no alerts and keeps nothing for you to review later. Use replay to look at a past session.
• It has no minimum-size and no minimum-base setting. The one fixed floor is 5000 contracts. Use Top moves, which ranks by contracts, to judge size.
• It does not read several days at once. The board is one trading date and one expiry. The insight card’s Day uses the previous close as its baseline.
• It does not read the live chain for the board. It reads the archive of saved snapshots, about a minute apart.
• It does not subtract the index’s move from a premium. A build-up name can be only a price move.
• It cannot say who traded, and it collects no volume.
• It does not forecast. The verdict has not been trained or backtested.
• It places no order.

The Numbers the Page Uses

Every number quoted in this guide is in one list (scripts/guides/oi-spurts-parts/limits.mjs). The most useful ones:

What We Have Not Verified

Which statements in this guide could we not confirm, and what should I check myself?

Everything this guide says about how the page behaves was read from the page’s own program code or taken from a picture of it. These are the items we could not confirm. Wherever the guide touches one it links here instead of stating it as a fact. For exchange rules we did not rely on memory: no official page was used, so none is stated.

If any of these is settled by an official source, the guide can be updated. Each has a place in Sources.

Glossary

What does each word mean?

Every word the guide uses that has a special meaning on this page, in the order a reader meets it.

Open Interest

The number of option contracts at a strike that are open: opened and not yet closed or settled. It counts positions, not trades. When one person opens and another closes with each other, it can fall even though trading was heavy.

Contract and lot

A contract here is one unit of the underlying; contracts are bought and sold in lots (65 for NIFTY, 30 for BANKNIFTY, 500 for RELIANCE in the pictures). The page counts Open Interest in contracts, so a lot of 65 adds 65.

Lakh and crore

Indian units. One lakh is one hundred thousand and one crore is ten million, or a hundred lakh. The page prints 52.93L for 52.93 lakh and 1.85Cr for 1.85 crore; under a lakh it prints K for thousand (6.2K is 6200).

Strike

The price level an option is written on. A strike has a Call and a Put, and each is a separate leg.

Call and Put

A Call gains when the price rises; a Put gains when it falls. The page names a leg as “23300 Call” or “22750 Put”.

Premium

The price of one option contract in rupees. On this page the premium of a leg is the price of that option itself, not the price of the index.

Leg

One option on the board: a strike and a side. A board of 21 strikes has up to 42 legs.

Spurt

A leg whose Open Interest moved, up or down, by at least the spurt bar, measured against the Open Interest that same leg held when the window opened. A spurt is a fast change in a leg’s own book. It says nothing about how large the change is in contracts.

Spurt bar

The percentage a leg’s own Open Interest must move to count as a spurt: 10, 20 or 30 percent, and 20 when the page opens. It marks and counts legs. It does not hide any.

Window

The stretch of the session a move is measured over: 5m, 15m, 30m, 1h or Day. Every percentage is measured from the snapshot the window opens at to the snapshot on the board.

Snapshot and archive

One recorded reading of the whole option book, taken about once a minute. The archive is the day’s snapshots for one expiry; the board is read from it, not from the five-second chain.

Build-up

The page’s name for what a leg’s Open Interest and premium did together: Long Buildup (both up), Short Buildup (Open Interest up, premium down), Short Covering (Open Interest down, premium up) and Long Unwinding (both down). Conventional readings, not named traders.

Flat and thin start

A leg that opened the window with 5000 contracts or fewer (or a premium of ₹0.05 or less) is read as flat: its percentage is shown as zero and it has no build-up, because a percentage of almost nothing is not information.

Frame fit

The rotation map fits its frame to the bulk of the board (97 percent of the contracts), so one far strike on a thin book cannot stretch it. The few loudest legs beyond the frame ride its rim and their card prints the real figure; no percentage is ever cut off.

Top moves

The page’s first view: four cards, one per build-up, each listing the contracts that moved the most Open Interest, loudest first, with the change in percent of the leg’s own book and in premium.

Trail and lead leg

A trail (the page calls it a path) is the line a leg has walked across the map since the window opened. The lead leg is the picked one, or the one that moved the most contracts if none is picked; its path is drawn bold, with the time it began.

Verdict and lean

The one phrase in the insight card, such as Bearish · new positions. It comes from two questions: are positions being opened or closed, and which way does the size that moved lean. It is a rule of thumb that has not been trained or backtested.

Opened, closed and turnover

Opened is the contracts added across the legs whose Open Interest rose; Closed is the contracts removed across the legs whose Open Interest fell; turnover is the two added together.

Loudest leg

The leg that moved the most contracts in the window, up or down. It is ranked by contracts, not by percentage.

Steps agreeing

Of the last three one-snapshot steps, how many moved the leg’s Open Interest the same way as the window did. 3 of 3 is a build still going on; 0 of 3 means it has paused or is easing.

Quiet

The verdict when too few contracts changed to read: fewer than 20 lots (or 0.05 percent of the Open Interest standing on the strikes read, if that is larger).

At the money

The strike nearest the index or share price. A Call is in the money below price and out of the money above it; a Put is the reverse.

Expiry

The date an option series ends. The board reads one expiry at a time, chosen under Contract in Customise.

Writing

Selling an option to open a position. Writers receive the premium and take the risk. Writing and buying both add to Open Interest; only the premium’s direction hints which was likelier.

Hedge and roll

A hedge is a position held against another; a roll moves a position to another strike or expiry. Each prints as a build-up on some leg and cannot be told apart from a new view.

Chart time and replay

Chart time moves the board to an earlier snapshot. Replay plays the board forward snapshot by snapshot from there. Neither is remembered when you leave.

Questions Readers Ask

What do readers ask most?

Short answers, each with the section that gives the full reasoning.

Sources

Where does each statement in this guide come from?

The guide rests on the program code of the OI Spurts page and on pictures of the page itself. The constants are quoted from one list (scripts/guides/oi-spurts-parts/limits.mjs); each row names the file the value comes from. No official exchange or regulator document is cited as proof of a rule in this guide; what we could not confirm is in What we have not verified.

Where Each Part Comes From

The Numbers the Guide Quotes

The Pictures

Each picture is a capture of the real page on an invented market, taken on 5 October 2026 at 2:20 pm by the page’s own clock. The strike ladder and each strike’s opening Open Interest are taken from a stored close file of 25 September 2026 and treated as the previous close; everything after that, the spot path, every premium and every change in Open Interest, is invented, with two far strikes given thin starting books on purpose. The pictures are regenerated with node scripts/guides/shot-oi-spurts.cjs and the figures quoted in the text are checked against figures.json, which that script writes, whenever the guide is built. Nothing in a picture is a market quote, and nothing in it happened.