r1b2kr1/pp1pq2n/nQ3bpp/3PPpP1/B1P2B2/P1N5/RP2P2P/5KNR b - - 4 21
FEN state: r1b2kr1/pp1pq2n/nQ3bpp/3PPpP1/B1P2B2/P1N5/RP2P2P/5KNR b - - 4 21 ; Best move: a7b6
The current state of the chess board is: Black rook at a8, black bishop at c8, black king at f8 and black rook at g8. Black pawn at a7, black pawn at b7, black pawn at d7, black queen at e7 and black knight at h7. Black knight at a6, white queen at b6, black bishop at f6, black pawn at g6 and black pawn at h6. White pawn at d5, white pawn at e5, black pawn at f5 and white pawn at g5. White bishop at a4, white pawn at c4 and white bishop at f4. White pawn at a3 and white knight at c3. White rook at a2, white pawn at b2, white pawn at e2 and white pawn at h2. White king at f1, white knight at g1 and white rook at h1. Both players have exhausted their castles. Half move number is 4. Full move number is 21. Black to move.