About this opening
Queen's Indian Defense: Petrosian Variation is an opening in the Encyclopedia of Chess Openings,
classified under code E12. ECO group E (E00–E99)
covers Indian defences against 1.d4, covering the Nimzo-Indian, Queen's Indian, King's Indian and Catalan systems. This particular variation is reached
after 7 half-moves from the
starting position, with the move sequence 1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. a3.
It belongs to the Queen's Indian Defense family. Within that family this is a sub-variation (the Petrosian Variation line).
The opening sequence in prose form: 1.d4 Nf6, 2.c4 e6, 3.Nf3 b6, 4.a3. From this position exactly one named continuation is recorded in the encyclopaedia.
Use the interactive board above to walk through the moves position-by-position. Click any move in the navigation to step backwards, or use the keyboard arrow keys. The list of recorded continuations sits directly below the board. For statistical data — how often master-level players have reached this position, White's win-rate, draw frequency, Black's score — see the panel in the right column.
Caissly's coverage of E12 extends through every named sub-variation in this line and across all four locales (English, Spanish, Portuguese, Russian). Where editorial commentary exists for a specific variation it appears as the page body; otherwise the page presents the structural data, board, and statistics as shown here.