Resignation Trap: Planinc made 5...b5 6. Bb3 Bb7 his pet line.
In an earlier round in this tournament (in which Planinc won first prize), Robatsch tried 7. d4 Nxd4 8. Bxf7+ Kxf7 9.Nxe5+ Kg8 10. Qxd4, but later only drew Robatsch vs A Planinc, 1969
Lutikov tried 7. c3 Nxe4 8. Re1 Nc5 9. Bd5 Be7 10. Nxe5 Nxe5 11. Bxb7 in the first round of the USSR-Yugoslavia match, played a little after this tournament Lutikov vs A Planinc, 1969
In round three of the USSR-Yugoslavia match, Lutikov tried to improve over Unzicker's 12. d5, with the waiting move, 12. a3. Planinc replied with the sacrifice 12...d5!? instead of the more restrained 12...d6. Lutikov vs A Planinc, 1969
Back to this game vs. Unzicker, Black plays a very pleasing kingside pawn advance, gaining momentum by harassing White's Queen, who eventually gets exiled after 32. Qb7
Notice that 34. Qxa6? loses to 34...Ra7
44...g3! is a neat decisive stroke. If White replies with 45. Bxc5, he then gets mated by 45...gxf2+ 46. Kxf2 Qh4+ 47. Kg1 Rxg2+!