Change in open interest in the chain is a close to close figure, not an intraday one
The chain the school uses is the close of 10 Jun 2026 for the 30 Jun 2026 expiry. Every open interest figure and every change figure in it is a close to close number. It says what was open at the close and how much it moved since the previous close. It does not say what happened between the two.
Intraday trading depends on prices and positions that change through the session. A closing chain cannot show that. The change in open interest for a day is the net result of all the trades in that day, and it can hide a position opened and closed inside the session. A reading taken at the close cannot tell you where the index will be an hour later.
Read the chain for the structure of the day's positions. Look at where open interest sits, how it moved since the previous close, and whether the price move that day agreed with it. The module on reading the option chain covers the columns, and the module on open interest covers the change.
The NSE option chain page updates through the session, and many people use it intraday. They watch where open interest is added or removed, the volume at each strike and how wide the quotes are. The dated chain has the first two, at the close, and not the third. The school does not use the page for reading, because a screen that changes minute by minute would turn into a signal. The dated chain is for learning the structure, and it should be read as history.
Before you trade. Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. Read the SEBI study