Oleg M Romanishin vs Janez Barle
Sukhumi Sukhumi 1970.??.??
Sicilian Defense: Sozin Attack 0-1

Oleg Romanishin vs Ulf Andersson
Biel SKA Biel SUI round 6 1996.07.28
English Opening: Anglo-Indian Defense, Grünfeld Formation 0-1

Oleg Romanishin vs Vahe Baghdasaryan
Schaakfestival Open A Groningen NED round 5 2010.12.26
French Defense: Diemer-Duhm Gambit 1-0

Olga Badelka vs Artem Smirnov
Chigorin Memorial St Petersburg RUS round 2 2016.10.16
Nimzo-Indian Defense: Normal Variation, Bishop Attack, Classical Defense 1-0

Olga Badelka vs Mariya Muzychuk
FIDE Grand Swiss Women Riga, Latvia round 3.7 2021.10.29
English Opening: Anglo-Indian Defense, Grünfeld Formation 1/2-1/2

Olga Girya vs Alisa Galliamova
Russian Championship Superfinal (Women) Ufa RUS round 10.3 2021.10.19
Slav Defense: Bonet Gambit 0-1

Oluwafemi Balogun vs Sebastian Mihajlov
Chess Olympiad Tromso NOR round 9.48 2014.08.11
Nimzo-Larsen Attack: Classical Variation 1-0

Omar Almeida Quintana vs Diasmany Otero Acosta
XXXVI Capablanca Mem Premier II Havana CUB round 5 2001.05.10
Queen’s Gambit Declined: Orthodox Defense, Alekhine Variation 1/2-1/2

Onni Sorakunnas vs Stig Miettinen
FIN theme4 corr 1965.??.??
Queen’s Gambit Declined: Albin Countergambit, Fianchetto Variation 0-1

Orn Leo Johannsson vs Pouya Idani
Reykjavik Open Reykjavik ISL round 1.22 2014.03.04
Döry Defense 0-1