Yamaguchi Noriyoshi served as a bushō during the Sengoku period. He was a retainer of the Oda and Imagawa clans.
Noriyoshi was born as the son of Yamaguchi Noritsugu, a retainer of the Imagawa clan. After the death of Oda Nobuhide in 1552, in the era of his son, Oda Nobunaga, Noriyoshi and his father abandoned the Oda in favor of the Imagawa. Nortisugu assigned Noriyoshi to defend Narumi Castle and then established a fortress in Kasadera and brought in forces from Suruga such as Okabe Motonobu. Noritsugu himself remained in Sakuranakamura Castle in Owari.
On 4/17 of Tenbun 22 (1553), Nobunaga, at the age of nineteen, led approximately 800 soldiers to attack Narumi. North of Narumi, to the east of Sannonyama in Konarumi, he discovered an advance by approximately 1,500 forces led by Noriyoshi in Akatsuka. Nobunaga then headed toward Akatsuka to commence an attack, triggering the Battle of Akatsuka. This clash, however, ended in a draw, after which the two sides exchanged captured soldiers and horses.
His father, Noritsugu, lured the lords of Ōdaka and Kutsukake castles away from the Oda to capture these sites. Okabe Motonobu, a retainer of the Imagawa, was assigned as the chamberlain of Narumi Castle.
Later, however, after being summoned to Suruga, Noriyoshi and his father were forced, upon orders of Yoshimoto, to commit seppuku. Nobunaga may have orchestrated the deaths of Noriyoshi and his father through deceptive tactics.