r1b1k1rB/p2q1pbp/n3p3/1NPp2p1/1P1n2PP/PQ1P4/4PP2/R4KNR w q - 5 21
FEN state: r1b1k1rB/p2q1pbp/n3p3/1NPp2p1/1P1n2PP/PQ1P4/4PP2/R4KNR w q - 5 21 ; Best move: b5d4
The current state of the chess board is: Black rook at a8, black bishop at c8, black king at e8, black rook at g8 and white bishop at h8. Black pawn at a7, black queen at d7, black pawn at f7, black bishop at g7 and black pawn at h7. Black knight at a6 and black pawn at e6. White knight at b5, white pawn at c5, black pawn at d5 and black pawn at g5. White pawn at b4, black knight at d4, white pawn at g4 and white pawn at h4. White pawn at a3, white queen at b3 and white pawn at d3. White pawn at e2 and white pawn at f2. White rook at a1, 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 5. Full move number is 21. White to move.