r1bbk2r/2p2ppp/np5n/3pp1q1/1QP1P3/2N2N2/P2PKP1P/R1B4R b k - 1 21
FEN state: r1bbk2r/2p2ppp/np5n/3pp1q1/1QP1P3/2N2N2/P2PKP1P/R1B4R b k - 1 21 ; Best move: a6b4
The current state of the chess board is: Black rook at a8, black bishop at c8, black bishop at d8, black king at e8 and black rook at h8. Black pawn at c7, black pawn at f7, black pawn at g7 and black pawn at h7. Black knight at a6, black pawn at b6 and black knight at h6. Black pawn at d5, black pawn at e5 and black queen at g5. White queen at b4, white pawn at c4 and white pawn at e4. White knight at c3 and white knight at f3. White pawn at a2, white pawn at d2, white king at e2, white pawn at f2 and white pawn at h2. White rook at a1, white bishop at c1 and white rook at h1. Black kingside is the only castle move available. Half move number is 1. Full move number is 21. Black to move.