r1b1k2r/3np1b1/1qpn1pp1/ppPp2PB/3PQP2/1P2B1KN/P2NP2P/R6R b - - 1 21
FEN state: r1b1k2r/3np1b1/1qpn1pp1/ppPp2PB/3PQP2/1P2B1KN/P2NP2P/R6R b - - 1 21 ; Best move: d6e4
The current state of the chess board is: Black rook at a8, black bishop at c8, black king at e8 and black rook at h8. Black knight at d7, black pawn at e7 and black bishop at g7. Black queen at b6, black pawn at c6, black knight at d6, black pawn at f6 and black pawn at g6. Black pawn at a5, black pawn at b5, white pawn at c5, black pawn at d5, white pawn at g5 and white bishop at h5. White pawn at d4, white queen at e4 and white pawn at f4. White pawn at b3, white bishop at e3, white king at g3 and white knight at h3. White pawn at a2, white knight at d2, white pawn at e2 and white pawn at h2. White rook at a1 and white rook at h1. Both players have exhausted their castles. Half move number is 1. Full move number is 21. Black to move.