Expert’s Choice: Koshu

Koshu (‘甲州’) is a white grape variety, with a name originating from the ancient name of Yamanashi prefecture in the central south of Honshu island.

It is the most-produced wine grape in Japan, and 96% of Koshu wines are produced in the Yamanashi prefecture, where plantings are estimated at about 450ha.

Production in 2018 reached almost 3,300 tonnes in Yamanashi, according to Japan’s national tax agency (though not all used for wine production), followed by 78t in Shimane and 27t in Yamagata.

Scroll down for Hayato Kojima’s pick of 18 Koshu wines to try

The story of the origin of the Koshu grape has two versions. One is that in the early 8th century, a well-respected Buddhist monk Gyoki brought this grape to Yamanashi from Nara (the nation’s capital at that time) and planted the first Koshu vines. Another explanation is that in the late 12th century, local resident Amemiya Kageyu found some wild grapes on the way home and planted the seeds.

A recent DNA study revealed the truth of its origin; Koshu sits within the family of Vitis vinifera. Its European parent was first brought to China via the Silk Road and naturally crossed with a native Asian species now known as Vitis davidii. It is possible that the Japanese official missions (or ‘Kentoshi’) to the Chinese Tang dynasty (AD618-907) brought back this European grape.

Flavour profiles

Koshu was consumed only as a table grape in Japan for a long time until the late 1800s when people started to use it for winemaking. The grape has pinkish grey-coloured berry clusters and thick skins. The wine tends to have a pale colour, featuring delicate citrus, Nashi pear and white peach aromas with minerality. Low to medium in alcohol, it usually has racy acidity on the palate with a crisp finish.

For years, Koshu was considered a lightly textured wine best shown in an unoaked, fresh and fruity style. However, in recent years, thanks to the efforts of ambitious local winemakers, consumers have begun to find sparkling Koshu or oaked, medium- to full-bodied Koshu, or even orange Koshu in the wine shops.

The Koshu essentials

Located about 100km west of Tokyo on the northern foothills of Mount Fuji, most of Yamanashi’s vineyards are on the bottom and the hillside of the fertile Kofu Basin. White varieties account for 62% of grape plantings in Yamanashi – unsurprisingly, Koshu (85% of the whites) ranks at the top, followed by Delaware (10.3%) and Chardonnay (1.8%).

Yamanashi – Japan’s first GI for wine, granted in 2013 – is a warm region, with annual heat summation levels similar to Tuscany in central Italy and Portugal’s Douro valley. Heavy rainfalls are seen in the flowering season (June) and during harvest in September, making it hard to produce concentrated, healthy crops.

Traditionally vine-growers adopt tall trellising to cope with the humidity, with the most popular pruning system being referred to as ‘X-line’, due to the pattern it forms in the overhead pergola. Nowadays, they also adopt straight-line spur pruning for lower yields, while in some top wineries, the ‘vertical shoot positioning’ system (VSP, in which fruit hangs in clusters beneath a narrow ‘curtain’ of upward-grown vine shoots) is gaining popularity, with improved grape quality and limited yields.

In terms of food pairing possibilities, the delicate, restrained characters of Koshu pair well with the classic ‘dashi’ flavour in Japanese home-made dishes featuring an umami-rich, savoury tone extracted from seafood and konbu (sea kelp). A wide variety of sushi, plain Japanese noodles and ramen with salt-based broth (shio ramen) are ideal pairing partners, too.

As for more Western foods, try Koshu with carpaccio, salade niçoise, light seafood meals such as ceviche, a fruits de mer platter or seafood paella. All the wines that follow are from the Yamanashi prefecture…

Hayato Kojima’s selection of Koshu wines to try

The wines are sorted by score in style order; sparkling, white and orange. 

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