The Battle of Suursaari was fought over the frozen Gulf of Finland on and around the islands of Gogland (Finnish: Suursaari) and Bolshoy Tyuters (Finnish: Suur-Tytärsaari) during the Second World War. After sharp fighting the numerically superior Finnish forces liberated Gogland and Bolshoy Tyuters, and later provided support for German forces defending Bolshoy Tyuters against Soviet counterattacks.