Hyūga Province
In 1561, the relationship between his clan and the Shimazu collapsed and Kanetsugu allied his clan with the Itō clan of Hyūga Province to counter Shimazu. In the same year, he repelled invading Shimazu troops with much success and killed the younger brother of Takahisa, Shimazu Tadamasa. Knowing that there was no turning back, Kanetsugu tried to divorce his wife who was of from the Shimazu clan, but she did not agree and declined the offer.