The Japan Wine Competition which takes place every year in Yamanashi within sight of Mount Fuji grows bigger each year along with the number of Japanese wines and wineries. This year there were close on 800 Japanese wines to be judged by five panels of tasters, with cooler regions such as Nagano, Yamagata and the northerly island of Hokkaido becoming ‘hot’, as it were, for burgundian varieties such as chardonnay and pinot noir, and sparkling wines.

The Yamanashi region remains at the hub of the growing Japanese wine universe because it’s by far the biggest producer of wines made from koshu, Japan’s own distinct native grape. Koshu joins a rollcall of Cinderella grape varieties such as pinotage and zinfandel for being hidden away until someone came along and applied the glass slipper treatment. In Japan that someone, Grace Winery’s Shigekazu Misawa , decided that if koshu were given the respect it deserved, in the vineyard and the cellar, it could become a princess in its own right.

Koshu’s problem is twofold. Firstly, it’s been weighed down by 1000-year old history as a table grape variety. It was only at the end of the 19th century that a fledgling wine industry began, but the traditional system of growing koshu remains mostly intact. In the system, massive Jack and the Beanstalk–like vines produce vast quantities of pink-skinned bunches of grapes hanging down from a high trellis. Secondly, Japan’s high rainfall and humidity makes getting the best out of koshu, or any grape for that mater, a highly labour intensive operation.

Mr Misawa meanwhile is on a mission to improve. He bought a vineyard, Akeno, and planted the vigorous koshu in a European-style vertical trellis to reduce yield and increase quality. While others pooh-poohed his efforts, he and his winemaker daughter Ayana, were vindicated when this year the 2013 Akeno Koshu won the first ever international gold medal for koshu wine at the Decanter World Wine Awards. It is a wonder of delicacy and concentration, the only bad news being that it’s made in too small quantities for export. His other four 2013 koshus should soon be on the water however and they are excellent.

Despite the fact that most koshu is still grown in the traditional way and therefore tends to dilution and simplicity, I can vouch for the fact from tasting the six gold medal-winning koshu in Japan that it is possible to produce beautiful dry whites of delicacy and concentration. Imports of koshu in the UK are still at an early stage but if you want an introduction to the grape, albeit without the complexity it’s capable of, Marks & Spencer has brought in the 2013 Sol Lucet Koshu from Kurambon, £12.99, a fragrant, light and delicate summer refresher.

Something for The Weekend

Night In

2011 Pacherenc du Vic-Bilh Duc de Termes, Plaimont

This honeyed sweet white from Plaimont, made from the Pyrenean grapes Petit and Gros Manseng, coats the tongue with a moreish glacé pineapple and stem ginger sweetness, bringing a new dimension to summer berries. £5.99, half-bottle, Tesco.

Dinner Party

2012 Pablo The Cubist Old Vine Garnacha Calatayud

Produced from old grenache vines on the stony slopes of Calatayud, this bright, imperious red shows opulently plump cherry and plum fruitiness with a seductive richness that’s balanced by a succulent texture and chunky finish. £9.99, Waitrose.

Splash Out

2013 Fillaboa Albariño, Rias Baixas

From Rias Baixas in Galicia, this albariño smells of fresh pear and almond tart, delivering a fresh prickle on the tongue and flowing across it with a bone dry, grapefruit zesty tang, leaving you satisfyingly refreshed. £17.95, Berry Brothers, TheDrinkShop.com.