Koshu

Koshu grapes have been present in Japan for over 1,000 years. The variety is believed to have travelled via the Silk Road from China during the 7th or 8th centuries, with one tradition crediting Buddhist monk Gyoki with introducing the grape at Daizenji Temple in 718 CE. For centuries, Koshu was grown primarily as a table grape. Commercial winemaking did not begin until the late 19th century, when the first formal wine company, Koshu Wine Company, was established in 1874. Two young men, Masanari Takano and Ryuken Tsuchiya, trained in France in 1877 and returned to establish Japan's first wine production company. The Katsunuma district of Yamanashi became, and remains, the heart of the Japanese wine industry.

• Grape tradition in Japan dates back over 1,000 years, linked to Silk Road trade routes
• Buddhist monk Gyoki is credited with introducing Koshu at Daizenji Temple in 718 CE
• Japan's first formal wine company established in 1874; Takano and Tsuchiya trained in France in 1877
• Katsunuma in Yamanashi is the historic and modern centre of Koshu wine production

Yamanashi Prefecture provides a distinctive growing environment for Koshu. Vineyards sit at elevations of 300 to 600 metres above sea level, with the most prized plots reaching 500 to 700 metres. The continental climate delivers significant day-to-night temperature variation, long sunshine hours, and the cooling easterly sasago oroshi breeze descending from the surrounding mountains. Soils are diverse, including clay, sand, volcanic material, decomposed granite, and ancient seabed sediments on alluvial fans with excellent drainage. Humid summers present a disease pressure challenge, which Koshu's naturally thick, pink skins help to mitigate.

• Vineyards at 300 to 700 metres elevation on alluvial fans with free-draining, diverse soils
• Continental climate with large diurnal temperature variation and long sunshine hours
• The sasago oroshi mountain breeze contributes to the grape's characteristic freshness
• Thick pink skins give natural resistance to disease in Yamanashi's humid summers

Koshu produces light-bodied, pale straw-coloured white wines with a soft, aromatic bouquet of citrus, peach, and jasmine, underpinned by mineral freshness and high acidity. Alcohol levels typically sit between 11 and 11.5% ABV. The variety is highly versatile: producers craft dry and off-dry still wines, sparkling wines, sur lie styles with added complexity, barrel-aged versions, and orange wines made with skin contact. Over 80 wineries now operate in Yamanashi Prefecture. Traditionally, vineyards used an X-shaped pergola system with paper hats placed over individual bunches for sun and rain protection. Modern producers increasingly employ vertical shoot positioning and sustainable or organic practices.

• Light-bodied with citrus, peach, and jasmine aromas; mineral-driven with high acidity
• Alcohol typically 11 to 11.5% ABV; dry to off-dry styles most common
• Produced as still, sparkling, sur lie, barrel-aged, and orange (skin-contact) wines
• Traditional pergola training with paper bunch covers; VSP and organic practices increasingly adopted

Koshu has steadily earned international acclaim. The grape was registered with the International Organisation of Vine and Wine in 2010 as the first variety indigenous to Japan, a milestone that opened doors to formal export markets. In 2024, Suntory Tomi Koshu 2022 became the first Japanese wine to win Best in Show at the Decanter World Wine Awards, a landmark achievement for the entire Japanese wine industry. Exports are growing to the UK, United States, Australia, and Europe, though distribution remains limited relative to domestic consumption. Notable producers include Grace Wine, Château Mercian, Katsunuma Jyozo Winery, Lumière Winery, Manns Wines, Suntory Tomi No Oka Winery, and Kurambon Wine.

• Registered with the OIV in 2010 as Japan's first officially recognised indigenous variety
• Suntory Tomi Koshu 2022 won Best in Show at the 2024 Decanter World Wine Awards
• Exports growing to the UK, US, Australia, and Europe
• Over 80 wineries in Yamanashi; Grace Wine and Château Mercian among the most prominent producers