was the third son of Tsunehisa

Amago Tsunehisa

was a powerful warlord who gained the hegemony in Chūgoku region, Japan starting as a vassal of the Rokkaku clan. He ruled the domains of Inaba, Hōki, Izumo, Iwami, Oki, Harima, Mimasaka, Bizen, Bitchū, Bingo, and Aki....

. His childhood name was Hikoshirō (彦四郎). He also called himself for the domain he ruled.

He received Enya of east Izumo Province

Izumo Province

was an old province of Japan which today consists of the eastern part of Shimane Prefecture. It was sometimes called . The province is in the Chūgoku Region.- History :It was one of the regions of ancient Japan where major political powers arose...

 and used Mount Yōgai (要害山) for his castle. Like his elder brother Kunihisa

Amago Kunihisa

was a son of Tsunehisa.Kunihisa's faction was named Shingūtō after the town, Shingu where it was based. He had been called "On the military matters, he is like a kami and a oni" from his father, Tsunehisa. But he often looked down on those who did not do well on the battlefield and was obnoxious...

, he was skilled in warfares. Not satisfied with the size of his domain, he demanded another 700 Kan in addition to 3000 Kan he already owned. He raised a revolt against Tsunehisa in 1532 suspecting Kamei Hidetsuna, the chief advisor to Tsunehisa had been plotting against him. The Amago clan split into two and Kamei Toshitsuna, Hidetsuna's younger brother died fighting for Okihisa. He was driven out of Enya and escaped. In 1534, he committed seppuku

Seppuku

is a form of Japanese ritual suicide by disembowelment. Seppuku was originally reserved only for samurai. Part of the samurai bushido honor code, seppuku was either used voluntarily by samurai to die with honor rather than fall into the hands of their enemies , or as a form of capital punishment...

realizing that he would never be able to return to the clan.