1r1qk1nr/1p6/5p2/p1PPpbPp/8/2NPPPP1/P3KR2/R1BQ1BN1 b k - 4 18
FEN state: 1r1qk1nr/1p6/5p2/p1PPpbPp/8/2NPPPP1/P3KR2/R1BQ1BN1 b k - 4 18 ; Best move: b7b5
The current state of the chess board is: Black rook at b8, black queen at d8, black king at e8, black knight at g8 and black rook at h8. Black pawn at b7. Black pawn at f6. Black pawn at a5, white pawn at c5, white pawn at d5, black pawn at e5, black bishop at f5, white pawn at g5 and black pawn at h5. White knight at c3, white pawn at d3, white pawn at e3, white pawn at f3 and white pawn at g3. White pawn at a2, white king at e2 and white rook at f2. White rook at a1, white bishop at c1, white queen at d1, white bishop at f1 and white knight at g1. Black kingside is the only castle move available. Half move number is 4. Full move number is 18. Black to move.