rn2kr2/p4ppp/1p4n1/1Nb5/1B1p1PP1/2P1P3/P5bP/RQ1K2NR b q - 3 21
FEN state: rn2kr2/p4ppp/1p4n1/1Nb5/1B1p1PP1/2P1P3/P5bP/RQ1K2NR b q - 3 21 ; Best move: b8a6
The current state of the chess board is: Black rook at a8, black knight at b8, black king at e8 and black rook at f8. Black pawn at a7, black pawn at f7, black pawn at g7 and black pawn at h7. Black pawn at b6 and black knight at g6. White knight at b5 and black bishop at c5. White bishop at b4, black pawn at d4, white pawn at f4 and white pawn at g4. White pawn at c3 and white pawn at e3. White pawn at a2, black bishop at g2 and white pawn at h2. White rook at a1, white queen at b1, white king at d1, white knight at g1 and white rook at h1. Black queenside is the only castle move available. Half move number is 3. Full move number is 21. Black to move.