rnb3nr/3k1p2/pp1pp2p/1qp1b1p1/P1P1PPP1/3P3N/RPQ4P/1NB1KB1R w K - 3 15
FEN state: rnb3nr/3k1p2/pp1pp2p/1qp1b1p1/P1P1PPP1/3P3N/RPQ4P/1NB1KB1R w K - 3 15 ; Best move: a4b5
The current state of the chess board is: Black rook at a8, black knight at b8, black bishop at c8, black knight at g8 and black rook at h8. Black king at d7 and black pawn at f7. Black pawn at a6, black pawn at b6, black pawn at d6, black pawn at e6 and black pawn at h6. Black queen at b5, black pawn at c5, black bishop at e5 and black pawn at g5. White pawn at a4, white pawn at c4, white pawn at e4, white pawn at f4 and white pawn at g4. White pawn at d3 and white knight at h3. White rook at a2, white pawn at b2, white queen at c2 and white pawn at h2. White knight at b1, white bishop at c1, white king at e1, white bishop at f1 and white rook at h1. White kingside is the only castle move available. Half move number is 3. Full move number is 15. White to move.