r1b1k1n1/3n4/p1p2ppr/N1b4p/2PP1P1P/3BP3/PP4P1/R1BQK2R w q - 4 21
FEN state: r1b1k1n1/3n4/p1p2ppr/N1b4p/2PP1P1P/3BP3/PP4P1/R1BQK2R w q - 4 21 ; Best move: d4c5
The current state of the chess board is: Black rook at a8, black bishop at c8, black king at e8 and black knight at g8. Black knight at d7. Black pawn at a6, black pawn at c6, black pawn at f6, black pawn at g6 and black rook at h6. White knight at a5, black bishop at c5 and black pawn at h5. White pawn at c4, white pawn at d4, white pawn at f4 and white pawn at h4. White bishop at d3 and white pawn at e3. White pawn at a2, white pawn at b2 and white pawn at g2. White rook at a1, white bishop at c1, white queen at d1, white king at e1 and white rook at h1. Black queenside is the only castle move available. Half move number is 4. Full move number is 21. White to move.