r1bqk1r1/p2p3n/npp3p1/4pp1p/1bPP3P/NP1KP3/PB3PP1/4RBNR b q - 3 15
FEN state: r1bqk1r1/p2p3n/npp3p1/4pp1p/1bPP3P/NP1KP3/PB3PP1/4RBNR b q - 3 15 ; Best move: b4e1
The current state of the chess board is: Black rook at a8, black bishop at c8, black queen at d8, black king at e8 and black rook at g8. Black pawn at a7, black pawn at d7 and black knight at h7. Black knight at a6, black pawn at b6, black pawn at c6 and black pawn at g6. Black pawn at e5, black pawn at f5 and black pawn at h5. Black bishop at b4, white pawn at c4, white pawn at d4 and white pawn at h4. White knight at a3, white pawn at b3, white king at d3 and white pawn at e3. White pawn at a2, white bishop at b2, white pawn at f2 and white pawn at g2. White rook at e1, white bishop at f1, 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 15. Black to move.