[Event "IBM"]
[Site "Amsterdam"]
[Date "1963.??.??"]
[Round "6"]
[White "Barendregt, Johan Teunis"]
[Black "Portisch, Lajos"]
[Result "1-0"]
[WhiteElo ""]
[BlackElo ""]
[ECO "C68"]

1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.O-O Bg4 6.h3 h5 7.d3 Qf6 8.Nbd2 g5
9.Re1 Be6 10.d4 exd4 11.e5 Qg7 12.Nxd4 O-O-O 13.Nxe6 fxe6 14.Qf3 Bb4 15.c3 Be7
16.Nb3 Nh6 17.Nd4 Rxd4 18.cxd4 Nf5 19.Qb3 Qg6 20.Be3 g4 21.Kf1 gxh3 22.gxh3 Nh4
23.Ke2 Qf5 24.Rg1 Rd8 25.Rg3 Qf7 26.Rag1 Nf5 27.Rg6 Rd5 28.Rg8+ Bd8 29.Qb4 Qd7
30.Bg5 Nxd4+ 31.Kf1 Qh7 32.Qf8 Qd3+ 33.Kg2 Qe4+ 34.f3 Qe2+ 35.Kh1 Qxf3+ 36.Qxf3 Nxf3
37.Bxd8 Rxd8 38.Rxd8+ Kxd8 39.Rf1 Nxe5 40.Re1 Nc4 41.b3  1-0

