He was born in a working-class family in Briše near Zagorje in the Central Sava Valley, in German-occupied Slovenia.

[3] However, his best result was achieved at the Amsterdam (IBM tournament) 1973, where he shared first place with Tigran Petrosian, ahead of Lubomir Kavalek, Boris Spassky and László Szabó.

[4] Planinc played on fourth board (+9 –1 =5) for Yugoslavia in the 21st Chess Olympiad at Nice 1974, where he won a team silver medal.

Planinc continued to suffer from severe depression for decades, spending the last years of his life at a mental institution in Ljubljana.

[6] In The Penguin Encyclopedia of Chess, Grandmaster Raymond Keene said of Planinc, "he specializes in apparently outdated openings into which his imaginative play infuses new life".