r1k3nr/1pp2ppp/p1n3b1/1PbBq3/P1P4P/6P1/1B2NP2/RN3RK1 b - - 4 21
FEN state: r1k3nr/1pp2ppp/p1n3b1/1PbBq3/P1P4P/6P1/1B2NP2/RN3RK1 b - - 4 21 ; Best move: e5b2
The current state of the chess board is: Black rook at a8, black king at c8, black knight at g8 and black rook at h8. Black pawn at b7, black pawn at c7, black pawn at f7, black pawn at g7 and black pawn at h7. Black pawn at a6, black knight at c6 and black bishop at g6. White pawn at b5, black bishop at c5, white bishop at d5 and black queen at e5. White pawn at a4, white pawn at c4 and white pawn at h4. White pawn at g3. White bishop at b2, white knight at e2 and white pawn at f2. White rook at a1, white knight at b1, white rook at f1 and white king at g1. Both players have exhausted their castles. Half move number is 4. Full move number is 21. Black to move.