He died last year in December at age of 64 years in retirement home. It's not exactly sure on which day, it is said that there was only one friend who visited him once in a while.

He was once suspended from playing chess for 3 years because of some incident. After those 3 years he won a tournament (playing after work) against Gligoric, Byrne and some other big ones. His mental health was going down after he got his GM title and later he quited chess completely. Not many Slovenians actually know who he was, he is more recognized around the world than in our country. Another Slovenian chess player that is recognized worldwide is Vasja Pirc - the man behind Pirc Defense.

Below are two more games, I tried to find some famous opponents, but you can see all his other games here: http://www.chessgames.com/perl/chessplayer?pid=17987

It's funny that Timman used Winawer variation of French defense against him in all 4 games and Planinc won all of them. They were all played in 1974, two of them in IBM tournament. Here is the shorter one:

Byrne also used Winawer variation against him and lost (Planinc's score against him is 1 win and 1 draw).

The second one is against Ulf Andersson (he was 4th player in the world at his peak):