Koshu Project

Koshu Project for the Future of Koshu Wine

Koshu is a grape with a beautiful pale purple skin, an indigenous Japanese variety used for wine production that has been grown in Katsunuma for over 1,300 years. Originating in the Caucasus region, the variety is said to have travelled along the famous Silk Road trading route and before eventually arriving in Japan.

Koshu grapes are thick-skinned and resistant to disease, rain and cold. Fresh with gentle acidity, the grapes have an aromatic character similar to Sauvignon Blanc.

Château Mercian started using the sur lie method in the 1980s to improve the quality of Koshu wines. We also developed a number of new styles by making use of elements in the grape skin to produce orange wine (Gris de Gris) and styles that bring out a citrusy aroma (Kiiroka). We share our technical innovations freely with other Japanese wineries in order to lead the Japanese wine industry towards a new level of quality.

The Koshu variety was found to contain Vitis vinifera DNA in 2004, and in 2010 the variety was registered by the International Organisation of Vine and Wine (OIV).

With its lighter alcohol content, delicate texture, fresh and gentle acidity and Japanese citrus fruit aroma, Koshu wines are turning heads in Japan and around the world.