r2qkb1r/1p2np2/pP5p/P2p1b2/2pp2Pp/N1PPQP2/4P3/1R2KBNR w K - 0 21
FEN state: r2qkb1r/1p2np2/pP5p/P2p1b2/2pp2Pp/N1PPQP2/4P3/1R2KBNR w K - 0 21 ; Best move: e3d4
The current state of the chess board is: Black rook at a8, black queen at d8, black king at e8, black bishop at f8 and black rook at h8. Black pawn at b7, black knight at e7 and black pawn at f7. Black pawn at a6, white pawn at b6 and black pawn at h6. White pawn at a5, black pawn at d5 and black bishop at f5. Black pawn at c4, black pawn at d4, white pawn at g4 and black pawn at h4. White knight at a3, white pawn at c3, white pawn at d3, white queen at e3 and white pawn at f3. White pawn at e2. White rook at b1, 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 0. Full move number is 21. White to move.