Kyoho
巨峰
Known as the "King of Grapes," Kyoho is a large, deep purple-black grape developed in Shizuoka Prefecture in 1942. It transformed Japan's grape industry in the postwar era and remains one of the country's most iconic cultivars, celebrated for its rich sweetness and abundantly juicy flesh.
About Kyoho
Kyoho was developed by independent breeder Yasushi Ōinoue in Shizuoka Prefecture, with crossbreeding beginning in 1937 and the new variety obtained in 1942. A cross between the female parent Ishihara Wase and the male parent Centennial, it is a large, deep purple-black grape that transformed Japan's postwar grape industry and long held the top domestic market share. A PVP application was filed in 1953, but in 1957 the Ministry of Agriculture rejected it on grounds of poor fruit set, uneven coloring, berry drop, and short shelf life. As a result, Kyoho carries no registration number and has spread nationwide as a publicly available cultivar that anyone may grow freely. It is cultivated primarily in Yamanashi, Nagano, and Fukuoka prefectures, and in recent years gibberellin treatment to produce seedless berries has made it a staple at Japanese tables.
Taste & Texture
Kyoho berries weigh approximately 10–15 g each, making them notably large, with a deep purple-black skin. Brix levels reach 18–20°, and the balance between sweetness and acidity delivers a rich, layered flavor. The abundant juice that floods out when you bite in is a hallmark of Kyoho that newer varieties like Shine Muscat cannot replicate. The skin is thick and slightly astringent, so berries are normally peeled before eating. Kyoho naturally produces seeds, but gibberellin treatment has made seedless fruit the standard at supermarkets in recent years.
Flavor profile
- Sweetness: Strong (Brix 18–20°)
- Acidity: Moderate
- Aroma: Berry-forward, deep and rich
- Texture: Abundantly juicy
Season
PEAK
Aug – Sep
Top Production Areas
Variety Comparison
vs. Shine Muscat
The two varieties differ sharply across skin color (deep purple-black vs. yellow-green), skin edibility (peel before eating vs. eat skin-on), aroma (berry-forward richness vs. Muscat fragrance), and texture (abundantly juicy vs. crisp). Kyoho is prized for its burst of juice and deep sweetness; Shine Muscat for its distinctive aroma and refreshing character — the choice comes down to use case and personal preference.
vs. Pione
Pione is a direct offspring of Kyoho (Kyoho × Cannon Hall Muscat), and the two share a similar deep purple-black appearance. However, Pione berries are even larger at 15–20 g each, with Brix equal to or slightly higher than Kyoho. The flesh is firmer and the fruit tends to keep longer. In the market it circulates mainly as seedless "New Pione," with Okayama Prefecture holding a dominant share.
Breeding History
Kyoho's development began in 1937 (Showa 12) at the Ōinoue Agricultural Research Institute in Tagata District, Shizuoka Prefecture (present-day Izu City). Breeder Yasushi Ōinoue used Ishihara Wase — a large-berry Okayama cultivar that is a tetraploid bud sport of Campbell Early, belonging to the Euro-American hybrid group — as the female parent, and Centennial, a European-type variety from Australia, as the male parent. The new variety was obtained in 1942 (Showa 17). Initially called by the line name "Ishihara Centennial," it was given the commercial name Kyoho ("Giant Peak") and spread to farmers together with its cultivation techniques amid postwar food shortages. Ōinoue applied for PVP registration in 1953, but in 1957 (Showa 32) the Ministry of Agriculture rejected the application due to defects including poor fruit set, uneven coloring, berry drop, and short shelf life. Without breeder's rights protection, Kyoho spread nationwide as a public-domain cultivar. Subsequent advances in growing technology and strong consumer popularity elevated Kyoho to "King of Grapes" status, and it became the catalyst for shifting Japan's grape industry from European-type varieties to American-cross cultivars.
- Breeder
- Ōinoue Agricultural Research Institute (bred by Yasushi Ōinoue, Izu, Shizuoka)
- Parentage
- Ishihara Wase × Centennial
How to Choose
-
Choose bunches where berries are evenly packed throughout and the stem is green and firm.
-
A uniform coating of white powder (bloom) on the berry surface is a sign of freshness.
-
Skin color should be a deep purple-black — the closer to a bluish-black, the more fully ripe the grapes tend to be.
-
Uneven coloring across a bunch may indicate incomplete ripening, so look for clusters with a uniformly deep purple-black color overall.
-
Berries whose attachment to the stem is secure and do not fall off when the bunch is gently shaken are a reliable indicator of freshness.
How to Store
-
Wrap the bunch loosely in paper towels or newspaper, place in a plastic bag, and store in the refrigerator vegetable drawer.
-
Wash only just before eating — avoid getting berries wet during storage.
-
Stored as a whole bunch, Kyoho keeps for about 3–5 days.
-
For longer storage, snip individual berries from the stem with scissors, leaving a small stub, and keep in an airtight container in the vegetable drawer for up to about one week.
-
To freeze, cut berries off the stem, place in a freezer bag, and enjoy half-thawed as a sorbet-like treat.
Frequently Asked Questions
When is Kyoho in season?
Early greenhouse-grown Kyoho begins appearing from late May. The peak season for field-grown fruit is late August through late September, with availability continuing until around October.
Can you eat Kyoho skin-on?
The skin is thick and somewhat astringent, so Kyoho is normally peeled before eating. Unlike Shine Muscat, it was not bred with skin-on consumption in mind.
Does Kyoho have seeds?
Kyoho is naturally a seeded variety, but gibberellin treatment to produce seedless fruit has become standard practice in recent years. The vast majority of commercially sold Kyoho can be assumed to be seedless. Widespread adoption of seedless production became common from the 2000s onward.
How do Kyoho and Pione differ?
Pione is a child variety of Kyoho and looks similar, but individual berries are even larger at 15–20 g, the flesh is firmer, and shelf life is better. It circulates in the market mainly as seedless New Pione, with Okayama Prefecture holding an overwhelming share.
Where are the main Kyoho-growing regions?
Nagano Prefecture is the largest domestic producer, followed by Yamanashi and Fukuoka (MAFF specialty fruit production survey). Yamanashi remains a major shipper to the Tokyo and wider Kanto wholesale markets.
Why does Kyoho have no PVP registration number?
A PVP application was filed in 1953, but in 1957 the Ministry of Agriculture rejected it on grounds of poor fruit set, uneven coloring, berry drop, and short shelf life. As a result, Kyoho spread nationwide without ever obtaining a registration number. It became a publicly known cultivar with no breeder's rights protection, and anyone remains free to grow it today.