r1bqk1n1/p2p3r/n1p4b/2p1ppp1/PPPP2Pp/7B/4PP1P/RNB2KNR b q - 0 16
FEN state: r1bqk1n1/p2p3r/n1p4b/2p1ppp1/PPPP2Pp/7B/4PP1P/RNB2KNR b q - 0 16 ; Best move: a6b4
The current state of the chess board is: Black rook at a8, black bishop at c8, black queen at d8, black king at e8 and black knight at g8. Black pawn at a7, black pawn at d7 and black rook at h7. Black knight at a6, black pawn at c6 and black bishop at h6. Black pawn at c5, black pawn at e5, black pawn at f5 and black pawn at g5. White pawn at a4, white pawn at b4, white pawn at c4, white pawn at d4, white pawn at g4 and black pawn at h4. White bishop at h3. White pawn at e2, white pawn at f2 and white pawn at h2. White rook at a1, white knight at b1, white bishop at c1, white king at f1, white knight at g1 and white rook at h1. Black queenside is the only castle move available. Half move number is 0. Full move number is 16. Black to move.