Kaiware Daikon Sprout Day (Kaiware Daikon no Hi)

What Is Kaiware Daikon Sprout Day?

September 18th is "Kaiware Daikon Sprout Day" (かいわれ大根の日) in Japan. It was established in September 1986 at a meeting of the Japan Kaiware Association (now the Japan Sprout Association). September was chosen because it was the month of that meeting. The 18th comes from a visual play on numbers: if you turn the "8" on its side (∞) and write a "1" beneath it, the shape resembles a daikon radish sprout with its two seed leaves spread out like a bamboo-copter. The day was created to help people become more familiar with kaiware daikon.

What Kind of Vegetable Is Kaiware Daikon?

Kaiware daikon is a type of "sprout" vegetable: daikon radish seeds are germinated, and the young stem (hypocotyl) and pair of seed leaves (cotyledons) are eaten.

• Origin of the name: Written 穎割れ or 貝割れ ("split shell"), it is said to be named for the way the seed coat splits and the two leaves open like a clam shell
• Flavor: It has a sharp, peppery bite like daikon, and is used in salads, rice bowls and as a colorful garnish for sashimi
• How it is grown: It is mainly grown hydroponically indoors—first kept out of the light to grow tall, then exposed to light at the end to turn the leaves green

Eaten Since the Heian Period

Kaiware daikon has a long history. It appears as "ōsai" (黄菜) in the Heian-period dictionary Wamyō Ruijushō, and as "sawayake soup" in the Utsubo Monogatari. The hydroponic mass-production system used today is said to have been devised by Maeda Takio, who lived on Nokonoshima Island in Fukuoka City.

Overcoming the Rumors of 1996

In 1996, a mass outbreak of O157 food poisoning linked to school lunches occurred in Sakai, Osaka Prefecture, and during the investigation, kaiware daikon was reported as a possible source of infection. Growers suffered severe damage from the resulting rumors, and the then Minister of Health and Welfare was shown in the news eating kaiware daikon to demonstrate its safety. Growers subsequently became even more focused on hygiene management.

Why the Association Changed Its Name

Many kaiware daikon growers also produce other sprouts, such as broccoli sprouts and pea shoots (tōmyō). As the range of varieties grew, the Japan Kaiware Association renamed itself the Japan Sprout Association in 2005.

How to Mark the Day

• Add kaiware daikon to a salad, chilled tofu or a rice bowl
• Write "18" as "∞" over "1" and see whether it looks like a kaiware sprout
• Compare the taste with other sprouts, such as broccoli sprouts
• Try growing kaiware daikon on a kitchen windowsill

A Day for a Small Vegetable, Born From the Shape of a Number

Kaiware Daikon Sprout Day is a unique anniversary that likens the number "18" to the shape of a kaiware sprout. Think of its long history, dating back to the Heian period, and the efforts of growers who overcame damaging rumors, and add a little kaiware to your table today.