r1bq1br1/3nkp1p/n1p5/pp1pp1p1/N1P5/NP1P4/P2BPPPP/R2QKBR1 w Q - 2 13
FEN state: r1bq1br1/3nkp1p/n1p5/pp1pp1p1/N1P5/NP1P4/P2BPPPP/R2QKBR1 w Q - 2 13 ; Best move: c4b5
The current state of the chess board is: Black rook at a8, black bishop at c8, black queen at d8, black bishop at f8 and black rook at g8. Black knight at d7, black king at e7, black pawn at f7 and black pawn at h7. Black knight at a6 and black pawn at c6. Black pawn at a5, black pawn at b5, black pawn at d5, black pawn at e5 and black pawn at g5. White knight at a4 and white pawn at c4. White knight at a3, white pawn at b3 and white pawn at d3. White pawn at a2, white bishop at d2, white pawn at e2, white pawn at f2, white pawn at g2 and white pawn at h2. White rook at a1, white queen at d1, white king at e1, white bishop at f1 and white rook at g1. White queenside is the only castle move available. Half move number is 2. Full move number is 13. White to move.