r3k2r/2ppqpb1/bpn5/p3p1pp/PP4P1/N1P5/3PPKPP/R1BQ1BNR w kq - 0 13
FEN state: r3k2r/2ppqpb1/bpn5/p3p1pp/PP4P1/N1P5/3PPKPP/R1BQ1BNR w kq - 0 13 ; Best move: b4b5
The current state of the chess board is: Black rook at a8, black king at e8 and black rook at h8. Black pawn at c7, black pawn at d7, black queen at e7, black pawn at f7 and black bishop at g7. Black bishop at a6, black pawn at b6 and black knight at c6. Black pawn at a5, black pawn at e5, black pawn at g5 and black pawn at h5. White pawn at a4, white pawn at b4 and white pawn at g4. White knight at a3 and white pawn at c3. White pawn at d2, white pawn at e2, white king at f2, white pawn at g2 and white pawn at h2. White rook at a1, white bishop at c1, white queen at d1, white bishop at f1, white knight at g1 and white rook at h1. Black kingside and black queenside castles are available. Half move number is 0. Full move number is 13. White to move.