Konnyaku Day

What Is Konnyaku Day?

May 29th is "Konnyaku Day" in Japan. It was established in 1989 by the National Federation of Konnyaku Cooperatives together with the Japan Konnyaku Association, and is registered with the Japan Anniversary Association. The date reflects the fact that konnyaku seed tubers are planted in May, as well as a play on numbers: "ko" (5) + "n(i)" (2) + "(ya)ku" (9) = "konnyaku." The day also encourages people to rediscover the benefits of konnyaku before the height of summer.

The Origin and Ingredients of Konnyaku

Konnyaku is made from the corm of the "konnyaku imo" (konjac, also called devil's tongue), a plant in the same family as taro. The tuber is processed into konnyaku flour or used raw, then combined with a coagulant such as calcium hydroxide to produce a food with its characteristic chewy texture.

• Raw material: Konnyaku tuber (konjac), believed to be native to India or the Indochina Peninsula
• Processing: Mashing, powdering, and coagulation
• Production: Gunma Prefecture accounts for over 90% of Japan's harvest

The History of Konnyaku in Japan

Konnyaku has a long history in Japan. There are various theories about when it arrived, but it appears in the Heian-period dictionary Wamyō Ruijushō. It was initially used in shojin ryori (Buddhist vegetarian cuisine), and as processing techniques developed, it later became a common item on ordinary household tables.

• Recorded in the Heian-period Wamyō Ruijushō
• Used as an ingredient in shojin ryori
• Around 1776, Nakajima Tōemon, a farmer in the Mito domain, is said to have devised the method of turning the tubers into powder

Konnyaku in Shojin Ryori

In shojin ryori, which avoids meat and fish, konnyaku has played an important role. Its chewy texture has long been valued for adding a satisfying quality to dishes.

Types and Shapes of Konnyaku

Konnyaku comes in several types depending on shape and production method.

• Ita-konnyaku (block konnyaku): The most common form
• Shirataki / ito-konnyaku (noodle-shaped konnyaku): Thin, noodle-like strands often used in hot pots
• Tama-konnyaku (ball konnyaku): Round pieces; skewered balls simmered in soy sauce are a Yamagata specialty

Konnyaku in Japanese Food Culture

Konnyaku is widely used in home cooking and regional dishes throughout Japan. It appears in simmered dishes, oden, stir-fries, and many other recipes.

• It was traditionally nicknamed the "stomach broom," as it was thought to clean out the digestive system
• As a low-calorie food containing dietary fiber, it has become known overseas as "konjac" or "konnyaku"
• In English, the plant has also been called "devil's tongue" after the shape of its flower

Ways to Enjoy Konnyaku Day

• Look into how konnyaku tubers are grown and where they are produced
• Compare regional konnyaku dishes
• Learn about the connection between shojin ryori and Japanese food culture
• Taste different types to see how processing affects texture

A Day to Rediscover a Supporting Player on the Japanese Table

Konnyaku Day on May 29th shines a light on an ingredient that often plays a supporting role in everyday meals. Konnyaku has developed in close connection with Japanese agriculture and food culture. Why not add a dish of oden or simmered konnyaku to your table today?