Koshu

Koshu is Japan's flagship wine grape, grown principally in Yamanashi prefecture in the basin west of Tokyo, under the shadow of Mount Fuji. Its berries are pink-skinned rather than green, and DNA analysis has shown it to be predominantly Vitis vinifera with a component of East Asian wild vine species in its ancestry — a genuinely unusual parentage, and evidence of an old journey along the trade routes from the Caucasus.

It was grown in Japan for well over a thousand years as a table grape before anyone made serious wine from it. Modern Koshu winemaking dates from the late nineteenth century and only became technically accomplished in the last few decades.

The wine is extremely delicate: pale, light-bodied, low in alcohol, with green citrus, white peach, a faint note of yuzu or grapefruit pith and a clean mineral finish. There is often a slight phenolic bitterness from the pink skins. Aromatic intensity is very low, and the wine's whole character is a matter of texture, restraint and a kind of quiet precision.

That restraint is a liability in international competition and an asset at the Japanese table. Koshu is one of the few wines that genuinely works with sashimi, sushi and delicate dashi-based cooking, where a more assertive white would simply flatten the food.

Producers have experimented with lees ageing, light skin contact and barrel fermentation to add weight, with mixed results — the risk being that the additions overwhelm the very thing the grape is valued for. Yamanashi remains almost the only place it is grown.