r1b2b1r/npp4p/p2kpp1n/3p3P/1P3pP1/N1PP3N/PRQ1PPB1/4K2R w K - 4 20
FEN state: r1b2b1r/npp4p/p2kpp1n/3p3P/1P3pP1/N1PP3N/PRQ1PPB1/4K2R w K - 4 20 ; Best move: h3f4
The current state of the chess board is: Black rook at a8, black bishop at c8, black bishop at f8 and black rook at h8. Black knight at a7, black pawn at b7, black pawn at c7 and black pawn at h7. Black pawn at a6, black king at d6, black pawn at e6, black pawn at f6 and black knight at h6. Black pawn at d5 and white pawn at h5. White pawn at b4, black pawn at f4 and white pawn at g4. White knight at a3, white pawn at c3, white pawn at d3 and white knight at h3. White pawn at a2, white rook at b2, white queen at c2, white pawn at e2, white pawn at f2 and white bishop at g2. White king at e1 and white rook at h1. White kingside is the only castle move available. Half move number is 4. Full move number is 20. White to move.