People have been crazy about sweet potatoes throughout the ages.

What is the appeal of sweet potatoes?
Unraveling the history of Japanese sweet potatoes starting from Kawagoe City.

"I call myself the biggest sweet potato nerd in Japan. Please feel free to ask me anything about sweet potatoes."
These are the words of Ayuki Hashimoto, CEO of Sweet Potato Company, who regularly disseminates information about sweet potatoes through various media outlets and lectures.
Sweet potatoes are an essential ingredient in Kirishima Shuzo 's Shochu production. We spoke to Hashimoto about the history of sweet potatoes, starting from Kawagoe City, Saitama Prefecture, which is an essential part of the story of the sweet potato's roots in Japan.

"Chestnuts are better than 9 ri (four ri) - 13 ri"
During the Edo period, sweet potatoes became all the rage in the city of Edo, along with this catchphrase. At the time, sweet foods that were affordable for the common people were rare. Kawagoe was located 13 ri (about 4 km) away from Edo, the center of consumption, but because it was connected to the city by a river, the heavy and bulky sweet potatoes could be transported by boat, and it became established as a production area.
"Kawagoe has a sweets culture. Sweet potato crackers and sweet potato natto are unique to Kawagoe, where sweet potatoes are very familiar," says Hashimoto. The Beniaka variety of sweet potato that has been cultivated in Kawagoe has a light flavor, and this characteristic has led to the spread of sweets making in the area.
The sweets culture has grown with the times, and Kawagoe has become a popular tourist destination. It is said that tourist sweet potato digging, which is now common throughout the country, also began in Kawagoe. The declaration of October 13th as Sweet Potato Day was made by the Kawagoe Sweet Potato Friendship Association in Kawagoe.

While the Kanto region, including Kawagoe, has a widespread sweet potato culture as a dessert, Kyushu produces more sweet potatoes for primary processing such as Shochu. One theory is that this is related to the fact that Kyushu's Shirasu Plateau is not suitable for growing rice.
Sake is not easy to make. However, there is a constant demand for alcohol as a way to show appreciation for daily life. As a result, the culture of Shochu made from easily available sweet potatoes, has taken root.
Kirishima Shuzo uses approximately 100,000 tons of sweet potatoes annually, a large proportion of Japan's total sweet potato harvest. Hashimoto has this to say about potato Shochu:
"Kyushu's sweet potato Shochu culture continues to support the demand for sweet potatoes. I think that's very valuable. What's more, some of the sweet potatoes used for Shochu are surprisingly delicious to eat as well. I feel like it would be a waste to just use them for Shochu, as they have so much potential."

Hashimoto's interest in sweet potatoes first began when he visited the Osaka Flower Expo in 1990 as a junior high school student. "At the time, topics like environmental destruction, desertification, and food crises were being discussed. So I started reading books and learned that in Japan, people had historically relied on sweet potatoes to sustain life during the Edo period and wartime. I thought they were an amazing food."
To Hashimoto, who was a junior high school student at the time, sweet potatoes seemed to sparkle.

In the Edo period, there was a person who was just as fascinated by sweet potatoes as Mr. Hashimoto.
Aoki Konyo, a Dutch scholar also known as the "Sweet Potato Professor," had been Research sweet potatoes for some time, believing that they were a necessary crop in times of famine because they were highly nutritious and easy to grow. After the Great Kyoho Famine occurred, Shogun Tokugawa Yoshimune also took notice of Aoki Konyo's sweet potato cultivation. This led to the spread of sweet potatoes throughout the country, and they helped to alleviate many famines that followed.
"Just as Aoki Konyo popularized sweet potatoes in Japan, I have always wanted to spread the word about sweet potatoes to countries with food problems. It would be interesting if one day there was a record of a Japanese person spreading the sweet potato in some country," says Hashimoto.

Sweet potatoes have traveled all the way to Japan, passing through the hands of many different people and crossing the ocean. In Pacific island nations, they are considered a sacred crop, and in some areas they are a treasured staple food.
What is the value of sweet potatoes that has spread all over the world? Kirishima Shuzo launched the Roots Project in 2009, and has been exploring the academic background of sweet potatoes. However, there are many mysteries surrounding their true origins, and the curiosity about sweet potatoes only grows.
Like Aoki Konyo and Hashimoto-san, Kirishima Shuzo Shuzo is one of the companies that has long been fascinated by sweet potatoes, which are so full of charm that they connect people across the ages.