r1b2bn1/pq2k1pr/1pP2pPp/3np3/2P4P/P4P2/RB1PQ1KR/1N3BN1 w - - 4 21
FEN state: r1b2bn1/pq2k1pr/1pP2pPp/3np3/2P4P/P4P2/RB1PQ1KR/1N3BN1 w - - 4 21 ; Best move: c4d5
The current state of the chess board is: Black rook at a8, black bishop at c8, black bishop at f8 and black knight at g8. Black pawn at a7, black queen at b7, black king at e7, black pawn at g7 and black rook at h7. Black pawn at b6, white pawn at c6, black pawn at f6, white pawn at g6 and black pawn at h6. Black knight at d5 and black pawn at e5. White pawn at c4 and white pawn at h4. White pawn at a3 and white pawn at f3. White rook at a2, white bishop at b2, white pawn at d2, white queen at e2, white king at g2 and white rook at h2. White knight at b1, white bishop at f1 and white knight at g1. Both players have exhausted their castles. Half move number is 4. Full move number is 21. White to move.