Ookurahonke was founded in 1896 in Kashiba, Nara Prefecture, and built its reputation almost entirely on the yamadai brewing method, which develops the sake starter naturally without adding commercial lactic acid, producing sake with strong character and pronounced acidity. After falling dormant when the third-generation owner fell ill, the brewery was revived by fourth-generation owner Takahiko Ookura, who returned from a corporate career to restart production with renewed commitment to yamadai and self-cultivated Hinohikari rice. Okura Iroha is a newer expression from the brewery, a junmai ginjo unfiltered raw sake that extends the house style into more contemporary territory.