The Battle of Rastarkalv () took place in AD 955 on the southern part of the island of Frei in the present-day Kristiansund Municipality in Møre og Romsdal county, Norway. This was one of several battles between the forces of King Haakon the Good and those of the sons of Eirik Bloodaxe (Eiriksønnene). After their father's death, Harald Greycloak and his brothers were allied against King Haakon with King Harald I of Denmark. Haakon had put up a warning system with cairns that would be lighted to tell of approaching war fleets. Therefore, the king was alarmed first with messengers at Nordmøre from Stadlandet. By placing ten standards far apart along a low ridge, Haakon gave the impression that his army was bigger than it actually was. Haakon managed to fool Eirik's sons into believing they w