During the late 1970s and early 1980s, he was a frequent training partner of Bobby Fischer, who stayed at his home in San Francisco for extended periods.

[5] Born in Athens, Greece, Biyiasis moved to Canada as a young boy, and grew up in Winnipeg and Vancouver.

[7] He played in the 1969 Closed Canadian Chess Championship at Pointe Claire, and finished in the middle of the field; Duncan Suttles won.

He represented Canada as second reserve on its bronze medal-winning team at the 1971 World Students' Olympiad in Mayagüez, Puerto Rico, where he scored 5/7 (+4 −1 =2).

Biyiasas won the Zonal Closed Canadian Championship, Toronto 1972, with 12/17, half a point ahead of Lawrence Day and George Kuprejanov.

It marked an enormous leap in class for him in just one year, from second reserve on the Canadian student team to national champion.

He won board medals on three occasions, including a silver and two bronzes, scored (+28 −7 =18) overall, for 70 per cent, and helped Canada to some of its best-ever team finishes in 1976 (8th) and 1978 (11th).

[28] One of his strongest career results came in a very strong field at Wijk aan Zee 1980, where he made 7½/13 to tie for 4th–6th places, as Browne and Yasser Seirawan won.

[5] Biyiasis's formation was influenced in the late 1960s when he joined a group of young masters mentored by Elod Macskasy.

Biyiasis tended towards King's Indian Attack formations, and aimed to get play into complex maneuvering channels.