At the foothills of the epic Mount Fuji lie the vineyards of Yamanashi. After travelling along the Silk Road through China the Koshu grape appeared in the prefecture, along with Buddhism, around 700AD and has been cultivated for wine production for the last 130 years. While Koshu is a uniquely Japanese varietal it does contain traces of Vitis Vinifera DNA where hybridisation occurred at some point throughout it’s lineage but the grape long ago localised itself and became native to Japan.
Primary production is focused in the Yamanashi region, the first wine-growing site to be granted a Geographic Indication in 2013 by the Japanese government. Located in central Japan, land locked with many high mountains surrounding the central Kofu basin, 27% of the area is dedicated to national parks and 78% is covered by forests; making it one of the most densely wooded prefectures in the country. The land is predominantly volcanic with layers of clay and gravel and the PH is low making it acidic and abundantly fertile- comparable to NSW in Australia.
The Yamanashi prefecture lies on the 35th latitude North, similar to California, southern Spain and southern Italy, but without the Mediterranean climate & experiencing only minimum winter rainfall. It is essentially an inland valley enjoying long hours of sunshine, daytime temperature variation and an average rainfall of 1k mm. 80% of the rain falls within the growing season around June/ July and there are the unique conditions of typhoon season in September alongside summer monsoons to contend with.
Although historically used to make predominantly sweeter wines the focus has changed over the last 20-30 years to the production of dry styles with awesome results. While fairly thick skinned, making them reasonably hardy, the Koshu grape has beautifully delicate aromatics, with notes of yuzu, peach, lemon & apricots. There can be a nuance of salinity and fine minerality alongside a hint of tannin but this presents as a kind of firmness, rather than grippy texture, adding to a balanced overall structure. The wines tend to be delicate, restrained and linear with a crisp and polished finish. Koshu could potentially be compared to Pinot Grigio, Muscadet, Assyrtiko or Semillion, depending on the winemaking. Due to the high acidity and low sugar of the grape the alcohol tends to hover around 11-12% with a characteristic racy yet subtle vibe. There are currently 600 hectares under vine with an annual production of over 7 million bottles.
The pale pink skinned berries form distinctive long clusters and are usually found hanging from canopies, Vinho Verde style, using the pergola trellising method, to combat excessive summer rain, humidity and potential rot, although VSP is becoming more common and yielding promising results. It’s not uncommon during the growing season to observe little hats painstakingly perched on bunches of berries to avoid excessive water saturation. While Biodynamic winemaking is yet to be explored in Japan, many winemakers are endeavouring to move towards organic certification and practise sustainable farming methods, an aspect full of both market and land-caring potential. Already many winemakers prefer spontaneous fermentation of indigenous yeasts rather than inoculation, offering another layer of integrity to the winemaking transformation.
2019 is a particularly good vintage for Japanese wines showing excellent concentration and keen acidity and each passing year the quality is reinforced and elevated. Delicate skin contact Koshu wines are making waves within the amber wine communities and the versatility of the grape never ceases to excite.
You can almost taste the attention to detail and pursuit of excellence, synonymous with the Japanese culture, in every sip.