Koshu Wine and Koshu Grape in Japan

20 December 2012
Teiji Takahashi

1 Koshu grape :Indigenous vitis vinifera in Japan

“Koshu” is an ancient name of region of Japan, located in the centre of Japan. Neither where is the origin of the grape, named “Koshu”, nor when the grape was introduced in Japan is clearly known. Two legendary stories exist concerning the origin of this grape.

The first story is that in 1186 Kageyu Amemiya in Katsunuma district, Yamanashi prefecture found by accident a peculiar wild vine/s in the field, and planted it in his land. Five year later, he succeeded in growing the vine with wonderful grapes. The second story is that the prominent monk, Gyogi, he planted seeds of vine, when he visited Katsunuma and ordered the construction of a temple “Daizennji” in 718.

Several old documents described that the cultivation of Koshu grapes had existed since around 1000 years ago in Japan. Therefore, this grape has been said to have been transferred from some region of Europe like Caucasus, crossing China, since Koshu grape does not exist in China. In addition, some people said that the Ryugan, Chinese vitis vinifera variety, is the origin of Koshu and others guessed that migrant birds brought seeds from China.

Upon request of Japan, the California University Davis confirmed that Koshu variety is vitis vinifera in 2004, Then, the National Institute of Brewing of Japan conducted a study to identify the origin of Koshu by the method of DNA analysis, and concluded that this variety is vitis vinfera, but one of varieties consisting the Asian group of vitis vinifera, different from that of European vitis vinifera. However, the rout of travel to Japan from Europe is still unknown.

In 2010, Koshu was registered in the list of grape varieties of the OIV (Organisation internationale de la vigne et du vin), which allowed Japanese wine makers to put “Koshu” on the label of wine to be exported to the European market, The variety was also listed as vitis vinifera in the Registry of the Foundation of Plant Service in the University of California Davis. 

2 Grapes for table grape and for wine

In Japan, grapes were produced as only table grapes for many years. According to some documents, grapes were grown in Kamakura period (1192-1333). During the Edo period, Koshu grapes were produced in Koshu (Yamanashi), Edo (Tokyo), Sagami (Shizuoka) and Kyoto regions, In particular, inhabitants of Edo consisted a big consumer of Koshu grapes. Accordingly, a quite large amount of fresh grapes were transported to Edo market, not so far from Koshu. Matsuo Basyo (1644-1694) described “Even umakos (horse conductor) bite grapes in Katsunuma, “ as Haiku (poem composed of 17 letters).

Just after the Meiji Restoration (1868), new government officials, who had visited Europe, were convinced that the wine production should be integrated in the industrial development policy. To save the rice to make alcohol was another objective in the situation of shortage of supply of rice to the population. Encouraged by the government, wine was produced for the first time in Katsunuma district. It was made of Koshu grapes. The government of Japan distributed seedlings all over Japan through the government breeding station, introducing vines from Europe and the USA. However, around 1884 Japan was already infected by phylloxera. In the condition of Japanese traditional eating habit, quite different from Europe, wine has not been well appreciated, then, gradually replaced by sweetened wine like port, which was largely made of American grapes, resistant to diseases and tolerant to humidity.

3 Koshu suit to the Japanese climate conditions

Koshu is late maturing variety. The color of grape is beautiful clear purple or pink. It is said sometimes “gris” like PinotGrigio and Gewurztraminer . Grape is comparatively large with thick skin, which has a function of resisting diseases. Among grapes there are spaces, not so dense in cluster (see picture 1), which contribute to the tolerance of humidity. These characters are considered to have been created by the natural selection process for many years in the Japanese climate conditions.

During 1000 years, farmers selected vines for table grape and for high yield as far as possible. Due to the fact, the vine of Koshu is now very luxuriant in vegetation, much more than European vitis vinifera. This character bring a difficulty to introduce the vertical training .Therefore, a special training system called “Itimonnji tansyo” (see picture 2) has been introduced. This method is to keep one or two long branch to be extended on the trellis training. At the moment, however, the vertical training like European style has largely adopted. Because of not sufficient experience, the most appropriate yield is still unknown. Some growers insist lower yield does not necessarily make good wine in case of Koshu grape.

                Picture 1   Kohu grapes

In particular, it was realized that Koshu grapes of very low sugar content and weak flavor were grown widely in the district, called “grapes without goût ”. Later a research institute found that it was caused by virus disease. In 1982,Manns Wine Company succeeded in producing virus free seedlings by meristem culture (成長点組織培養), which were distributed to growers . However, the low acidity and weak flavor remained as problems. Accordingly, the University of Yamanashi conducted a line selection (系統選抜), confirming the sugar content, degree of tartaric and malic acid .


Picture 2   Ichimonji Tansyo Training

4  Improvement of Koshu wine quality

Due to the higher standard of living and the change of eating pattern after the War, the consumption of genuine wine started in Japan, triggered by Tokyo Olympic Games (1964) and by Osaka International Exhibition (1970). Along with this trend, since 1970’s, efforts for improvement of quality of Japanese wines, produced of grapes grown in Japan, were initiated, introducing European varieties (vitis vinifera). Later, indigenous varieties, such as Koshu, Muscat-Bailey A and Zenkoji were re-evaluated.

Large wineries such as Mercian (Kirin), Suntory, Manns (Kikkoman) worked for this purpose, together with medium and small size wineries based on the district. At first, since 1970’s fresh and fruity wine was produced by the low temperature fermentation and purification of must. This type of wine keeps slight sweetness which could attenuate the bitterness coming from skins of grapes.

In 1990’s efforts to make dry Koshu started. Large wineries and medium size wineries participated in and contributed to the improvement toward dry higher quality. One of promoters is Mr Misawa (Grace Wine) based on the district.

In the course of efforts for dry good Koshu, following oenological practices were progressively identified and applied to make good Koshu wine. To improve rather flat taste of Koshu due to the low content of sugar and low level of acidity, the Sur lie method has been tried by M. Osakada and M. Kagayama in Mercian. Mr. Asai disseminated this technology in the region. He had a firm conviction that the unfavorable environment of Japan could be overcome, in terms of making good wine in Japan, and encouraged young wine makers to make good Japanese wine in later stage of his life. He (Mercian) already released “Kikyogahara Merlot” (Grand gold medal at Vino Ljubljana International Competition in 1989) and other wines like “Hokushin Chardonnay”.

At the same time of trial of Sur lie , concentration of must by reverse osmotic membrane(逆浸透膜) has been researched by the University of Yamanashi, Mercian and Manns and others. However, this practice has not been widely adopted, since the bitterness was accentuated, and the appliance was very costly. On the other hand, freezing concentration of must is considered to be more practical, in increasing sugar content, acidity and freshness, resulting in well balanced must. To add body, barrel fermentation and aging have been introduced. The result was good in general. However, some producers avoid use of oak barrel. Their opinion is that barrels may kill very subtle flavor or aroma of Koshu.

Finally, extraction of potential aroma has to be mentioned. Professor Tominaga (Japanese) of Bordeaux University identified the potential aroma of Koshu grape. Mercian , in the collaboration with him, developed the practices to effectively extract this aroma with the appropriate management of cultivation, fermentation and aging. This aroma is derived from some precursors (origin of aroma, 前駆体) of 3MH (3-mercaptohexan-1-01). In addition, these concentrations of precursors-3MH are varied during grape development (Kobayashi, Mercian). The aroma is like grapefruit. The precursor of aroma is contained at the highest level some time before the complete maturation of grapes.

Moreover, 3MH concentration of wine is affected by heavy metals, oxygen, and some phenols. For example, wines made from grapes sprayed with agrichemicals that contain many copper compounds are known to have low v3MH concentration. Therefore, the meticulous care in both cultivation and fermentation is needed.

Meanwhile, wine makers invited foreign enologists and prominent critics of wine in the process of improvement of Koshu. For example, The owner of the group Bernard Magrez estimated the great potential of Koshu, associated with Aruga, wine maker of « Katsunuma winery », they produced  « Magrez–Aruga Koshu »  Mr. Denis Dubourdieu, professor of enology at the University of Bordeaux worked four vintages (2004 to 2007) at Mr. Misawa’s winery . Mr. Singer (American), importer of wine based in Japan, encouraged producing fine wine with Koshu and worked in collaboration with Mr. Misawa. In December 2004, Robert M. Parker Jr gave it a score of 87/88 on a scale of 100.

After the KOJ (Koshu of Japan) was formed by 14 wine makers, aimed at improvement of quality of wine and promotion of export, Jancis Robinson (British) and Lynne Sheriff (South African) , Masters of Wine and Yuka Ogasawara (Japanese) have been invited as advisor of the KOJ.

Under on going process of elaboration of better Koshu, there are, at the moment, wide variations in Koshus. Wineries are relying on a different level of chaptalization to increase alcohol level. Some wine makers are experimenting with oak-barrel aging to add a body to the wine. Growers of grapes sometimes provide wine makers with grapes of low sugar and low acidity content. Due to the inexistence of proper wine law and geographical indication system in Japan, it is impossible to be certain what wine makers add to their wines. The city of Koshu, including Katsunuma district , therefore, introduced a system of Appellation d’Origine, in 2010, while the central government has not yet set up a legislation of the geographical indication .

5 Delicate taste of Koshu

Madame Jancis Robinson( advisor of the KOJ, Master of wine) wrote in 2010 on the flavor of Koshu, “ As for specific flavours, I found yuzu (a Japanese citrus) in some, lychee in others, and a professional Japanese wine writer assured me that quince (マルメロ) was the fruit she found most often in Koshu”. She also describes the mating of Koshu with foods. “ The better examples do seem to go particularly well with sashimi - and indeed any sort of raw fish dish including oysters, with sushi, tempura, and rice - even some gentler-flavoured risottos. There seems to me to be something quintessentially Japanese about a fine Koshu. The word Zen keeps coming to mind.

Madame Kumiko Okuyama (Vice Principal of the Academie du Vin au Japon) makes comments on the Koshu wine and its taste in 2012 as below.

In Japan, for many years it has been believed that the wet condition during the growing seasons of vines prevents making good grapes for wine. However, the quality has been dramatically improved for recent ten years, due to the advanced technology all over the world since 1990’s. some ambitious wine makers are producing full-blown dry wine with distinct flavor of fruits, which has been highly appreciated in both Japan and foreign countries.
Through more than 1000 years history of cultivation of Koshu vines, the trellis training has been widely adopted. Under this method, a vine had commonly 500 clusters by a vine. Therefore, the yield was very high. In recent years efforts are made for limiting such high yield. The good grapes were used to be placed on the market for table grapes, and others were used to be allocated to wine making. The wine produced by such way had not distinct taste and rather sweet, and was sold as souvenir for tourists. Even at the moment, the majority of wine is slightly sweet or demi-sec, while the level of quality has been improved.
Grace winery producing top quality of Koshu adopted the vertical training in 2005. Under the limited yield such as 20 clusters by a vine, the wine with concentrated flavor of matured fruits has been produced since 2009 vintage. This dry and high quality wine has a potential of pairing not only Japanese cuisine but also delicate type of French cuisine.Katsunuma Jozo, largest winery of Koshu wine, produces high quality wine in identifying characters derived from the separate fermentation of grapes in each parcel of vineyard. The wine is slightly sweet. The wine produced in Katsunuma district, center of Koshu, has become fine year by year.
Koshu wine is very delicate and not so conspicuous character, the majority of wine is produced by the fermentation in stainless steel tanks so as to be clean and fresh. The aroma consists of citrus fruit, white flower, or fruits candy. The astringent character which comes from peals is left as after taste. The wine goes well with susi, simple cuisine leaving the natural elements of ingredients, salad and grill of marine products. On the other hand, the Koshu wine of Burgundy style, fermented or matured in oak barrel, well pairs with light cuisine such as meuniere of fish, cream stew, broiled chicken (yakitori), deep fried pork (tonkatsu), as the wine has volume and complexity. Koshu wine, different from occidental white wine, presents delicately the core taste in deep behind the modest flavor. Accordingly, we can enjoy foods together with Koshu wine without unease.   


Tara – Wine Passionista, critic of wine, describes the taste of Koshu as below.

“I recently attended a tutored tasting led by two Masters of Wine, Jancis Robinson and Lynne Sheriff, where we tasted 10 wines, including 1 sparkling, all made from the grape variety Koshu.
It is different to anything I’ve tasted before – honestly.
There is pronounced acidity in the wines, meaning they are very fresh and refreshing, but in almost the exact opposite way a New Zealand Sauvignon Blanc is refreshing.  While a NZ Sauvignon Blanc will be intensely aromatic with pungent flavours that almost make your mouth pucker, the Koshu was soft, delicate – almost dainty.
Some of the wines were slightly more potent than others, but certainly the overall theme was subtlety and delicacy. It would make sense that they would pair perfectly with sushi and sashimi and I would be curious to see how they do with other cuisines. Some people in the room mentioned they’d had Koshu with a variety of foods before and they admitted being surprised at how well the wines complemented the food .”

6 Promotion of export of Koshu

The export of Koshu started in 2004 and 2005 to the USA. In recognition that Koshu were becoming the first Asian wine to draw international attention, several wine makers formed a group, called KOJ (Kosyu of Japan) in 2009. Inspired by Mr Asai’s remarks on the reason why Japan was left behind the USA and Australia in terms of making good wine is no challenge to open up the British market, the KOJ, led by Mr Misawa, has focused the promotion on London market at first.
In 2010 and 2011 the KOJ made a promotion of Kosyu in London. In 2012 the promotion was extended to Paris, where the OIV headquarters assisted the promotion.

Now, the KOJ and other wine makers are trying to open up the Asian market .Both European and Asian markets seem to be positive so far, while the quantity is not so great.


                                  Picture 3   Promotion in London 2011

Participants of the promotion in Paris are following wine makers.

Alps Wine,  Grace Wine,  Haramo Wine,  L'Orient Wine,  Lumière,  Marquis Winery
Mercian,  Rubaiyat Wine (Marufuji Wine),  Sadoya,  Soryu Winery,  Tomi no Oka Winery SUNTORY ,  Yamanashi Wine,  Yamato Wine

Annex I

Winners of gold medal and silver medal of the category of Koshu in Japan Wine Competition of 2012

Gold medal

     Name of Wine

   Name of Wine Maker

Tugai 2011

Yamato Wine

Suntory Japan Premium Koshu 2011

Suntory international

Koshu Dry 2011

Chateau Sakaori

Haramo vintage Koshu sur lie 2011

Haramo wine

2011 Rubaiyat Koshu sur lie

Marufuji Wine

Chanmoris Barrel Matured Koshu 2010

Morita Koshu Winery

Katsunuma Koshu Barrel Fermented 2010

Chateauraise Belle Foret Winery

Fuji Claire Koshu Barrel Fermented 2011

Fujikko winery

Silver medal

Koshu Verdegno 2011

Honbo Mars Winery

Lunaris Koshu Barrel Fermantation 2011

Manns Wine

Chateau Mercian Katsunuma Koshu 2011

Mercian Wine

Grace Koshu 2011

Grace Wine

Chateau Mars Koshu Sirane sur lie 2011

Honbo Mars Winery

L'Orient Katunuma Koshu 2011

Shirayuri Syuzo

L'Orient Koshu Barrel Fermented 2011

Shirayuri Syuzo

L'Orient Koshu Barrel Fermented 2009

Shirayuri Syuzo

Mercian Awa Murasaki 2011

Mercian Wine

Fuji Claire Koshu sur lie 2011

Fujikko Winery

2011 Rubaiyat Koshu

Marufuji Wine

Koshu Barrel Fermentation  2011

Gomi Winery

Grace Koshu in Barrel

Misawa Wnery

Fuji Claire Koshu sur lie 2011

Fujikko Winery

Titibu Wine sur lie 2010

Tichibu Wine

Chateau Mercian Koshu Barrel Fermentaion

Mercian Wine

Chanmoris Citus Aroma Koshu 2011

Morita Koshu winery

Flavuor Koshu Dry 2011

Oizumi Wine

2011 Rubaiyat Koshu Barell Fermentation

Marufuji Wine

Katsunuma Koshu sur lie 2011

Chateauraise Belle Foret wine

Kosyu sur lie 2011

Sasaiti Syuzou

Tomino Oka Koshu 2011

Suntory International

Koshu sur lie 2011

Shikisima Syuzou

Gassan Wine Soleil Le pin Koshu sur lie 2011

Syounai Takagawa

  Agricultural Cooperative

Traditional Rich Taste Koshu 2011

Soryu Wine

Cuvé  Misawa Koshu Toriibira

Private Reserve 2011

Misawa Winery

 Grace Gris de Koshu 2011

Misawa Winery

 Grace Koshu Toriibira 2011

Misawa Winery

 Grand Polaire Yamanashi Katsunuma

  Koshu Special Cuvé  2011


Sapporo Wine

Soryu Koshu 2011

Soryu wine                    

Annex II

Production of Koshu grapes in Japan




























         Ministry of Agriculture  2005


This document was mainly prepared on the basis of the discussions of Wine Challenge Symposium held on 9 June 2012 at the University of Tokyo.
Participants in presentations and discussions were Kazuhiko Kobayashi( University of Tokyo), Shigekazu Misawa(Grace wine), Hironori, Kobayashi (Mercian), Thihiro Takei (Manns) and Hiroto Maruyama (Restaurant, Aux amis des vins).

Teiji Takahashi

Lecturer , Tokyo University.

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