Kikkawa Motoharu was the second son of Mōri Motonari, and featured prominently in all the wars of the Mōri clan. He became an active commander of the Mōri army and he with his brother Kobayakawa Takakage became known as the “Mōri Ryōsen", or “Mōri's Two Rivers" (毛利両川).

Mōri Motonari was a prominent daimyō in the western Chūgoku region of Japan during the Sengoku period of the 16th century. The Mōri clan claimed descent from Ōe no Hiromoto (大江広元), an adviser to Minamoto no Yoritomo. Motonari was called the "Beggar Prince". He was known as a great strategist who began as a small local warlord (jizamurai) of Aki Province and extended his clan's power to nearly all of the Chūgoku region through war, marriage, adoption and assassination.