[Event "IBM"]
[Site "Amsterdam"]
[Date "1969.??.??"]
[Round "4"]
[White "Portisch, Lajos"]
[Black "Ivkov, Borislav"]
[Result "1-0"]
[WhiteElo ""]
[BlackElo ""]
[ECO "A07"]

1.Nf3 d5 2.g3 c6 3.Bg2 Bg4 4.d3 e6 5.Nbd2 Bd6 6.O-O Nd7 7.e4 Ne7 8.b3 O-O
9.h3 Bh5 10.Bb2 Rc8 11.Qe1 c5 12.Nh4 Qb6 13.Qe3 Rfe8 14.Qg5 Bg6 15.exd5 Nxd5
16.Nxg6 hxg6 17.Bxd5 exd5 18.Qxd5 Qc7 19.Nc4 Re6 20.Rae1 Rce8 21.Nxd6  1-0

