rn2k1nr/p2p2b1/4p3/2p3pp/1PB5/2PPpP1P/PQ4PR/RNB1K1N1 b Q - 4 18
FEN state: rn2k1nr/p2p2b1/4p3/2p3pp/1PB5/2PPpP1P/PQ4PR/RNB1K1N1 b Q - 4 18 ; Best move: c5b4
The current state of the chess board is: Black rook at a8, black knight at b8, black king at e8, black knight at g8 and black rook at h8. Black pawn at a7, black pawn at d7 and black bishop at g7. Black pawn at e6. Black pawn at c5, black pawn at g5 and black pawn at h5. White pawn at b4 and white bishop at c4. White pawn at c3, white pawn at d3, black pawn at e3, white pawn at f3 and white pawn at h3. White pawn at a2, white queen at b2, white pawn at g2 and white rook at h2. White rook at a1, white knight at b1, white bishop at c1, white king at e1 and white knight at g1. White queenside is the only castle move available. Half move number is 4. Full move number is 18. Black to move.