Caissa Codex
D41

Queen's Gambit Declined: Semi-Tarrasch Defense, San Sebastian Variation trainer

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Type a move and press Enter: e4, Nf3, O-O, or from and to squares like g1f3 (e7e8q to promote). The board is also played with the mouse.

Practise the Queen's Gambit Declined: Semi-Tarrasch Defense, San Sebastian Variation

Play Black's moves of the line from memory — 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 c5 7. Nf3 cxd4 8. cxd4 Bb4+ 9. Bd2 Qa5 — and the trainer plays White's replies; "Play the other side" turns it around.

Read about the line, its statistics on Lichess and Stockfish's evaluation on the Queen's Gambit Declined: Semi-Tarrasch Defense, San Sebastian Variation page, or pick another opening in the opening trainer.

https://chesscodex.org/train/queens-gambit-declined-semi-tarrasch-defense-san-sebastian-variation