r1q1k1n1/1p1np1b1/p1p4r/3Q1ppP/1P1P2P1/NbP1P1R1/P3K1N1/1RB2B2 b q - 2 21
FEN state: r1q1k1n1/1p1np1b1/p1p4r/3Q1ppP/1P1P2P1/NbP1P1R1/P3K1N1/1RB2B2 b q - 2 21 ; Best move: b3d5
The current state of the chess board is: Black rook at a8, black queen at c8, black king at e8 and black knight at g8. Black pawn at b7, black knight at d7, black pawn at e7 and black bishop at g7. Black pawn at a6, black pawn at c6 and black rook at h6. White queen at d5, black pawn at f5, black pawn at g5 and white pawn at h5. White pawn at b4, white pawn at d4 and white pawn at g4. White knight at a3, black bishop at b3, white pawn at c3, white pawn at e3 and white rook at g3. White pawn at a2, white king at e2 and white knight at g2. White rook at b1, white bishop at c1 and white bishop at f1. Black queenside is the only castle move available. Half move number is 2. Full move number is 21. Black to move.