About this opening
Queen's Gambit Declined: Semi-Tarrasch Defense, Main Line is an opening in the Encyclopedia of Chess Openings,
classified under code D42. 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 13 half-moves from the
starting position, with the move sequence 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c5 5. cxd5 Nxd5 6. e3 Nc6 7. Bd3.
It belongs to the Queen's Gambit Declined family.
Within that family this is a level-2 branch (the Semi-Tarrasch Defense → Main Line line). The immediate parent line is Queen's Gambit Declined: Semi-Tarrasch Defense, transitioned via 7.Bd3.
The opening sequence in prose form: 1.d4 Nf6, 2.c4 e6, 3.Nf3 d5, 4.Nc3 c5, 5.cxd5 Nxd5, 6.e3 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 D42 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.