r1q2b1r/3npkpp/b6B/pppP1p2/P2P3P/1P1R4/2QNPPP1/1N2KB1R b K - 2 21
FEN state: r1q2b1r/3npkpp/b6B/pppP1p2/P2P3P/1P1R4/2QNPPP1/1N2KB1R b K - 2 21 ; Best move: c5d4
The current state of the chess board is: Black rook at a8, black queen at c8, black bishop at f8 and black rook at h8. Black knight at d7, black pawn at e7, black king at f7, black pawn at g7 and black pawn at h7. Black bishop at a6 and white bishop at h6. Black pawn at a5, black pawn at b5, black pawn at c5, white pawn at d5 and black pawn at f5. White pawn at a4, white pawn at d4 and white pawn at h4. White pawn at b3 and white rook at d3. White queen at c2, white knight at d2, white pawn at e2, white pawn at f2 and white pawn at g2. White knight at b1, white king at e1, white bishop at f1 and white rook at h1. White kingside is the only castle move available. Half move number is 2. Full move number is 21. Black to move.