大西園製茶工場大西園
Oonishien (大西園製茶工場) is a 14th-generation tea farm and factory in Negishi, Iruma, Saitama, at the heart of the Sayama tea region. The official site describes the business as founded in the late Edo period with roughly 250 years of history and handling cultivation, processing, and sales in-house. Under current owner Nakajima Tsuyoshi (中島毅), the estate specializes in premium Sayama green tea, especially deep-steamed tea and hand-rolled tea, and the official product and shop pages reviewed on 2026-03-28 listed sencha, hand-rolled tea, black tea, hojicha, and tea bags but no matcha products.
Brand story
Oonishien says it has preserved Sayama tea craft since the late Edo period while adapting to modern demand through in-house cultivation, processing, and sales. The farm highlights traditional hand-rolled tea technique, deep-steamed Sayama tea production, and the stewardship of Nakajima Tsuyoshi, the first recipient of the title 永世茶聖 after eight national first-place wins in the National Hand-Rolled Tea Competition. The official profile also notes recent exports into the EU.
Supports: The official product archive reviewed on 2026-03-28 listed hand-rolled tea, sencha, black tea, hojicha, and tea bags; no matcha products were present.
Supports: Official address is 259 Negishi, Iruma, Saitama 358-0034, with retail hours 10:00-18:00 and Wednesday as the regular closing day.
Supports: Nakajima Tsuyoshi is the 14th-generation owner, born in 1979, and the first recipient of the title 永世茶聖 after eight national first-place wins in the National Hand-Rolled Tea Competition; the page also notes EU exports.
Supports: Official overview describes Oonishien as an Iruma, Saitama tea estate with about 250 years of history and an official online shop.
Supports: The plantation page lists nine cultivars grown in Iruma and states that Oonishien produces traditional Sayama deep-steamed tea.
Supports: Brand overview, product lineup (sencha, hand-rolled tea — no matcha), owner Nakajima Tsuyoshi profile
Sayama Tea Industry Promotion Association — Oonishien
Supports: Address 埼玉県入間市根岸259; 250 years tradition; 4 Agricultural Minister Awards; wholesale and retail
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