Tamenobu was successful in taking castle after castle in the region due to the divided state of the Nanbu clan, but realising that in the long term he would need to solicit outside help, he approached the Mogami clan for an introduction to the regime of Toyotomi Hideyoshi. Tamenobu initially departed by boat from Ajigasawa, but inclement winds blew the boat north as far as Matsumae. He made attempts to reach Hideyoshi overland in 1586, 1587 and 1588, but was blocked each time by hostile forces in the territories to the south of Tsugaru.
Tamenobu's strategy involved capitalizing on the Nanbu clan's internal divisions to capture castles, but he understood that long-term success required alliances with other powerful clans. He sought an introduction to Toyotomi Hideyoshi through the Mogami clan and attempted to reach him by land multiple times, but was blocked by hostile forces in Tsugaru's southern territories.