About this opening
Modern Defense: Kotov Variation is an opening in the Encyclopedia of Chess Openings,
classified under code A42. ECO group A (A00–A99)
covers flank and irregular openings, including the English, Bird, Réti and Dutch defences. This particular variation is reached
after 8 half-moves from the
starting position, with the move sequence 1. d4 g6 2. c4 Bg7 3. Nc3 d6 4. e4 Nc6.
It belongs to the Modern Defense family. Within that family this is a sub-variation (the Kotov Variation line).
The opening sequence in prose form: 1.d4 g6, 2.c4 Bg7, 3.Nc3 d6, 4.e4 Nc6. From this position the encyclopaedia records no further canonical continuations — practical play branches into unnamed transpositions or returns to the parent line for alternative ideas.
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. 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 A42 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.