2b1kb1r/1pq1p1p1/3p1p2/1r2n2p/P3P3/N1p2P1n/1BQP2PP/RNR2K2 w k - 1 21
FEN state: 2b1kb1r/1pq1p1p1/3p1p2/1r2n2p/P3P3/N1p2P1n/1BQP2PP/RNR2K2 w k - 1 21 ; Best move: a3b5
The current state of the chess board is: Black bishop at c8, black king at e8, black bishop at f8 and black rook at h8. Black pawn at b7, black queen at c7, black pawn at e7 and black pawn at g7. Black pawn at d6 and black pawn at f6. Black rook at b5, black knight at e5 and black pawn at h5. White pawn at a4 and white pawn at e4. White knight at a3, black pawn at c3, white pawn at f3 and black knight at h3. White bishop at b2, white queen at c2, white pawn at d2, white pawn at g2 and white pawn at h2. White rook at a1, white knight at b1, white rook at c1 and white king at f1. Black kingside is the only castle move available. Half move number is 1. Full move number is 21. White to move.