r1b1k1r1/pBpp1p1p/nb2p3/4P3/P5p1/q2P4/1PPN1PPP/RnBQ1KNR w q - 3 18
FEN state: r1b1k1r1/pBpp1p1p/nb2p3/4P3/P5p1/q2P4/1PPN1PPP/RnBQ1KNR w q - 3 18 ; Best move: a1a3
The current state of the chess board is: Black rook at a8, black bishop at c8, black king at e8 and black rook at g8. Black pawn at a7, white bishop at b7, black pawn at c7, black pawn at d7, black pawn at f7 and black pawn at h7. Black knight at a6, black bishop at b6 and black pawn at e6. White pawn at e5. White pawn at a4 and black pawn at g4. Black queen at a3 and white pawn at d3. White pawn at b2, white pawn at c2, white knight at d2, white pawn at f2, white pawn at g2 and white pawn at h2. White rook at a1, black knight at b1, white bishop at c1, white queen at d1, white king 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 18. White to move.