Chess puzzle (Advantage)
Opening: Vant_Kruijs_Opening, Vant_Kruijs_Opening_Other_variations
Moves: 1. e3 e5 2. c3 c5 3. Qb3 Nf6 4. Nf3 Nc6 5. d4 cxd4 6. cxd4 exd4 7. Nxd4 Nxd4 8.
exd4 d5 9. Be3 a6 10. Nc3 Be7 11. Be2 O-O 12. Bf3 a5 13. Bxd5 *
Position (FEN): r1bq1rk1/1p2bppp/5n2/p2B4/3P4/1QN1B3/PP3PPP/R3K2R b KQ - 0 13
Black to move.
Themes:  Middlegame  
Puzzle rating: 2004
Best move: a4