1Nb1k1nr/3p3p/r1q4b/2PN2p1/Qp1PpPP1/4p2P/R3P1BR/4K3 b k - 2 21
FEN state: 1Nb1k1nr/3p3p/r1q4b/2PN2p1/Qp1PpPP1/4p2P/R3P1BR/4K3 b k - 2 21 ; Best move: a6a4
The current state of the chess board is: White knight at b8, black bishop at c8, black king at e8, black knight at g8 and black rook at h8. Black pawn at d7 and black pawn at h7. Black rook at a6, black queen at c6 and black bishop at h6. White pawn at c5, white knight at d5 and black pawn at g5. White queen at a4, black pawn at b4, white pawn at d4, black pawn at e4, white pawn at f4 and white pawn at g4. Black pawn at e3 and white pawn at h3. White rook at a2, white pawn at e2, white bishop at g2 and white rook at h2. White king at e1. Black kingside is the only castle move available. Half move number is 2. Full move number is 21. Black to move.