Oleg Neikirch vs Mikhail Botvinnik
Leipzig ol (Men) fin-A Leipzig GDR round 1.2 1960.10.28
Sicilian Defense: Sozin Attack, Fischer Variation 0-1

Oleg Romanishin vs Adam Tukhaev
Team Championship of Ukraine Alushta UKR round 1 2005.04.07
Döry Defense 1-0

Olga A Andreieva vs Salme Rootare
6th Soviet Team Cup Riga URS 1968.12.??
Bishop’s Opening: Urusov Gambit 1-0

Olga Badelka vs Anna M Sargsyan
European Championship (Women) Vysoke Tatry SVK round 4 2018.04.11
Slav Defense: Czech Variation, Classical System 1-0

Olga Dolzhikova vs Yeonhee Cho
Chess Olympiad (Women) Tromso NOR round 1.2 2014.08.02
Italian Game: Bird’s Attack 1-0

Olga Girya vs Leya Garifullina
Russian Championship Superfinal (Women) Ufa RUS round 6 2021.10.14
Nimzo-Indian Defense: Hübner Variation 1/2-1/2

Olga Girya vs Natalia Pogonina
Russian Championship Superfinal (Women) Moscow RUS round 7 2012.08.10
Queen’s Gambit Declined: Tartakower Defense 0-1

Orkhan Abdulov vs Sergei Zhigalko
4th Al Ain Chess Classic Al-Ain UAE round 1.7 2015.12.23
Sicilian Defense: Najdorf Variation 1/2-1/2

Orrin Frink vs Francis J Le Count
New York Metropolitan tt New York, NY USA round 10 1923.04.07
Amazon Attack: Siberian Attack 0-1

Ortvin Sarapu vs Ilija Ilic
Adelaide Open Tt Adelaide, Australia round 3 1990.??.??
Döry Defense 1-0