The founder of the company is said to be "Niemon," who came from the province of Kaga (present-day Ishikawa Prefecture) around the end of the Warring States Period to the beginning of the Edo Period, and is still called "Kaga-nin" in Yuzawa today. Initially, he was an oil merchant, but later he also brewed miso. Ryoseki Sake Brewery was originally founded in 1874 by Ito Niemon Shouten. The name Ryoseki is said to have come from the association with the sake brand Masamune (Masamune = authentic), which was named by a sword connoisseur doctor during the reign of Niemon VIII, who wanted the sake to be both the famous sword of the east, Masamune, and the sword of the west, Munechika, and the sword of the east and west, Ozeki.