Olga Alexandrova vs Vladimir Savon
October GM Ukraina 1999.??.??
Nimzo-Indian Defense: Normal Variation, Gligoric System 1/2-1/2

Olga Badelka vs Wiktoria Smietanska
World Blitz Women 2021 Warsaw POL round 1.46 2021.12.29
English Opening: Anglo-Indian Defense 1-0

Olga Stjazhkina vs Maxim Vladimirovich Turov
Chigorin mem St. Petersburg RUS round 1 1999.11.02
Nimzo-Larsen Attack: Classical Variation 0-1

Oliver Mihok vs Alexander Bakin
European Individual Championship Rijeka CRO round 7 2010.03.12
Caro-Kann Defense 1-0

Oliver Mihok vs Miragha Aghayev
World Junior Championship Athens GRE round 4 2012.08.03
Ruy Lopez: Berlin Defense 1-0

Oliver Reeh vs Christian Mann
Bundesliga 2008/09 Various GER round 5 2008.11.29
French Defense: Tarrasch Variation, Botvinnik Variation 1-0

Oluwafemi Balogun vs Marko Makaj
PRO Chess League (Central) chess.com INT round 2 2017.01.18
Nimzo-Larsen Attack: Classical Variation 1-0

Orest Popovych vs Boris Spassky
87th US Open Somerset, NJ USA round 3 1986.08.05
King’s Gambit Accepted: Becker Defense 0-1

Orla Hermann Krause vs Jorgen Moeller
Copenhagen Copenhagen DEN round 6 1907.08.??
Sicilian Defense: Classical Variation 1/2-1/2

Orlando Pla vs Kachaya Mostafavi-Kachani
Moscow ol (Men) fin-C Moscow URS round 2 1956.09.11
King’s Indian Defense: Four Pawns Attack 1-0