r1b3r1/N2pn1k1/npp2p1p/P5p1/P1PPp3/B4P1P/4P1P1/1RQ1KBNR w K - 1 21
FEN state: r1b3r1/N2pn1k1/npp2p1p/P5p1/P1PPp3/B4P1P/4P1P1/1RQ1KBNR w K - 1 21 ; Best move: a5b6
The current state of the chess board is: Black rook at a8, black bishop at c8 and black rook at g8. White knight at a7, black pawn at d7, black knight at e7 and black king at g7. Black knight at a6, black pawn at b6, black pawn at c6, black pawn at f6 and black pawn at h6. White pawn at a5 and black pawn at g5. White pawn at a4, white pawn at c4, white pawn at d4 and black pawn at e4. White bishop at a3, white pawn at f3 and white pawn at h3. White pawn at e2 and white pawn at g2. White rook at b1, white queen at c1, white king at e1, white bishop at f1, white knight at g1 and white rook at h1. White kingside is the only castle move available. Half move number is 1. Full move number is 21. White to move.