Kidney Bean Day (Ingen Mame no Hi)

What Is Kidney Bean Day?

Every year on April 3rd is "Kidney Bean Day" (Ingen Mame no Hi). It commemorates the death, on April 3rd, 1673, of Ingen Ryūki, a Buddhist monk who came to Japan from Ming China and is credited with bringing kidney beans ("ingen mame," literally "Ingen's beans") to Japan. Master Ingen was the founder of the Ōbaku school of Zen Buddhism and is also said to have introduced sencha tea, watermelon, lotus root, and other foods to Japan. This day honors his contributions and encourages us to reappreciate the value of this everyday legume.

Historical Facts About Master Ingen and Food Culture

It's a rare story -- a bean named after a high-ranking monk.

• Fucha cuisine: Master Ingen introduced "fucha ryōri," a style of Chinese vegetarian cuisine. This style of sharing large communal plates had a major impact on Japanese food culture at the time, and kidney beans spread as an important ingredient in this cuisine.
• What "ingen mame" originally referred to: It's widely believed that what Master Ingen actually brought was what we now call the hyacinth bean (fuji mame). The bean we now call "ingen mame," introduced from the West in the late Edo to Meiji period, came to bear his name due to its similar shape.

Scientific Facts About Kidney Beans and Health

Kidney beans are a superfood, with the "essence of life" packed into each small bean.

• A treasure trove of protein and fiber: Kidney beans are rich in plant-based protein, including high levels of the essential amino acid lysine, making them an excellent complement to a grain-based diet. They're also rich in insoluble fiber, which supports gut health and helps moderate blood sugar spikes.
• Lectin toxicity and the importance of cooking: Raw kidney beans contain a natural toxin called lectin. Thorough cooking eliminates this toxicity, making the beans safe and nutritious -- a fact that underlies the long tradition of cooking beans by boiling them.

Interesting Facts About Kidney Beans

• The many foods Master Ingen brought: Besides beans, he's also said to have introduced bamboo shoots, lotus root, and watermelon, dramatically broadening the variety of foods available to people in Japan at the time -- truly a "benefactor" of Japanese cuisine.
• Names around the world: In English, they're called "green beans" or "common beans." They're among the most widely grown and consumed legumes in the world, and their origin in Mexico and Central/South America has been scientifically confirmed.
• "Sandomame" (three-harvest beans): Because they grow quickly and can be harvested up to three times a year, they're sometimes called "sandomame" in the Kansai region. They're known for being tough enough for beginner home gardeners.
• Vine vs. bush varieties: Kidney beans come in "vining" and "non-vining" varieties. Vining types can grow over 3 meters long, with an astonishing growth rate as they reach for sunlight.
• Color and nutrition: When eaten as green beans (sayaingen), they also provide vitamin A (beta-carotene) and vitamin C. They play an important role not just as a colorful garnish in Japanese cuisine, but as a nutritional balancer too.

Tips for Enjoying Kidney Bean Day

• Add kidney bean dishes -- sesame-dressed beans, tempura, or simmered beans -- to your April 3rd menu, and savor the simple, deep flavor that grows richer with every bite
• Reflect on the spirit of "wagō" (harmonious gathering) embodied in the fucha cuisine and sencha tea ceremony that Master Ingen brought to Japan, and spend some time enjoying a calm conversation with loved ones over a meal
• Use the fiber and protein in beans to gently care for your stomach and body, which can be worn down by the busy start of the new fiscal year
• Plan to grow kidney beans in a planter. Watching the seeds sprout and the vines grow rapidly is a small source of everyday wonder

The Wisdom and Vitality in a Single Bean

April 3rd is a day to reflect on how much a single bean, carried across the sea, has enriched Japanese food culture. What Master Ingen brought wasn't just an ingredient -- it was the joy of "eating together" and a spirit of gratitude toward nature. Just as a small kidney bean quietly but surely prepares to sprout in the soil, your own steady efforts will eventually bear fruit. Savor these nourishing beans, recharge your energy from within, and stretch out toward the new season like a vigorous green vine reaching for the sun.