About this opening
Queen's Gambit Declined: Semi-Tarrasch Defense is an opening in the Encyclopedia of Chess Openings,
classified under code D40. ECO group D (D00–D99)
covers closed games and semi-closed games beginning 1.d4 d5, covering the Queen's Gambit, Slav, Grünfeld and related queen-pawn structures. This particular variation is reached
after 8 half-moves from the
starting position, with the move sequence 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c5.
It belongs to the Queen's Gambit Declined family. Within that family this is a sub-variation (the Semi-Tarrasch Defense line).
The opening sequence in prose form: 1.d4 Nf6, 2.c4 e6, 3.Nf3 d5, 4.Nc3 c5. From this position 5 named continuations are recorded in the encyclopaedia, each leading to a distinct theoretical line.
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 D40 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.