Koshu, best-known indigenous grape variety in japan. The pink-skinned table grape has thick skins and withstands Japan’s humid summers relatively well. Most Koshu is pergola-trained but most ambitious growers are reducing yields via Ichimonji-Tansho, a high culture system with spur pruning, while the likes of Grace have started to train it low on cordon de royat, reducing yields further and producing some of the most concentrated examples of Koshu. Koshu wine can rarely be accused of an excess of flavour but it can be a fine accompaniment to sashimi. Still, sparkling, sweet, and oaked versions are made. dna profiling by Nami Goto in 2014 suggested that Koshu is a natural hybrid between an as-yet-unidentified variety of Vitis vinifera and an unknown variety, which is itself a hybrid between an individual of Vitis davidii and another unidentified variety of Vitis vinifera.