[FEN "rnbqk2r/1pp2pp1/p3p2p/4B2n/P1BPP2b/2N2PP1/1P5P/R2QK1NR b KQkq"]

10... Be7 11. f4


w b wb bw | w b wb bw

b     an
    


10...Be7      an
    


11. f4      an