[Event "Custom initial position (Black to play)"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[FEN "rnbqk2r/pppp1ppp/5n2/2b1p3/2B1P3/5N2/PPPP1PPP/RNBQ1RK1 b kq - 0 4"]
[SetUp "1"]

4... O-O *
