A long line for the unprecedented "Tsubo-yaki" experience. The story behind the birth of "Ginza Tsuboyaki-imo" and its special recipe

The name of the shop is "Ginza Tsuboyakiimo". In this article, we interviewed the developer about the story behind the birth of this unique shop and the particular details behind the product's creation. We bring you a heartwarming article that will make a great souvenir from your trip, asking "Why baked sweet potatoes in Ginza?"

Those wonderful baked sweet potatoes again

It opened in June 2018. The key person behind the store, which was born after about two years of planning and development, was Kanako Nakajima, art director at Hakuhodo Creative Vox. We asked her about the story behind its creation.

"The idea came from a roasted sweet potato stand that Shakunaga Kazuo, president of Toyama-based company Daiichi Rental Co., Ltd., saw in Ginza more than 50 years ago. When Shakunaga came to Ginza as a young man, he saw people eating roasted sweet potatoes hungrily around the stand. He never forgot the scene, and the smiles of the customers left a strong impression on him. Half a century has passed since then, and as Shakunaga approached 70, he wanted to revive that scene, so the project began to take shape."

Upon further investigation, I found that an essay written in the late Taisho period by Ikeda Yasaburo, a Japanese literature scholar from Ginza, mentioned that there was a sweet potato baker in Ginza that used pots. Pot-baked sweet potatoes take longer to cook than stone-baked sweet potatoes and are difficult to sell from a mobile vendor, so perhaps the number of pot-baked sweet potatoes has decreased over time. So what are the benefits of pot-baked sweet potatoes?

"It is baked slowly and gently in a pot using indirect heat, which gives it a rich sweetness and moist texture. Another feature is that the honey that has dissolved from the sweet potato is heated and gives it a fragrant taste, which is similar to caramel."

The pots are completely handmade by Tokoname-yaki craftsmen in Aichi Prefecture. Up to 15 sweet potatoes can be roasted at once in one pot, and a specialized "potato roaster" carefully checks the doneness of the sweet potatoes as they are roasted.

They also tried out a variety of heat sources, including charcoal, gas, and electricity, and experimented to find the best one. They eventually settled on charcoal, which is difficult to handle but produces a fragrant roast. They use high-quality binchotan charcoal, which can reach high temperatures and is very stable, to create a delicious dish that is one rank above the rest.

"We also had a hard time choosing the sweet potato. After trying many varieties, we decided on 'Beni Haruka,' which is known for its sticky deliciousness. Furthermore, we use 'matured sweet potato,' which is matured for a long time at low temperature to concentrate the flavor."

The concept is "roasted sweet potatoes that can be given as a gift"

Since sweet potatoes vary by region depending on the season, they use the most delicious variety and origin at the time, such as Ibaraki or Miyazaki. On busy days, they sell over 500 baked sweet potatoes at the store. They have three different sizes, and I was shown their products.

Hakuhodo Creative Vox normally proposes product names and package designs to a variety of companies, but for Ginza Tsuboyakiimo, they were entrusted with not only the naming and design but also everything from the concept to the form in which it is served.

"In a sense, I had a lot of freedom, but I also had a lot of responsibility. I learned a lot from many new experiences, and I only had positive worries. I visit the store about three days a week, and the best part is being able to see the reaction of the media directly through the customers."

Ginza is where all the best things from Japan and abroad come together. When they opened their shop in this area, one of the things they aimed for was the concept of "roasted sweet potatoes that can be used as gifts." Therefore, in addition to selling them individually, they also offer sets with a Tamatebako motif, which can be used as souvenirs from Tokyo or as gifts.

The store is open until 10pm on weekdays, which is long for a baked sweet potato specialty store. It also offers delivery to nearby areas, so it is popular with women who work at high-end clubs.

The rich yet elegant "Tsubo Yakiimo" is also available in ice cream form

Finally, it was time to try one. I ordered the "whole stick" and when I cut it open, the sweet aroma of sweet potato hit me along with the soft steam that wafted out.

The first bite is plump. As you chew it, the texture changes to a sticky one in your mouth, and at the same time, a rich, fragrant, sweet flavor spreads throughout your mouth. It has a refined flavor that is not sticky. It is said to be delicious even when cooled, so the flavor makes it a perfect gift.

"We opened in June during the hot season, so we also offered cold 'Ice Yakimo' sweet potatoes, which also proved popular and can be enjoyed all year round. What makes them unique is that after baking, they are frozen instead of refrigerated. They contain plenty of honey so they don't become hard and have a milky texture like ice cream."

This one also leaves an impression with its new texture that melts smoothly in your mouth. It's an unprecedented taste, like eating a rich potato yokan or Japanese sweets made with sweet potatoes. If you like sweet potatoes, it might be a good idea to buy both and compare the taste.

Ginza Tsuboyakiimo is so popular that it sometimes closes early due to long lines and when the sweet potatoes sell out. When asked about the best time to go, they said that you can line up and buy them right after the store opens. On the other hand, there may be a wait time for the sweet potatoes to be grilled in the evening, and they tend to get crowded on Saturdays, so please keep this in mind if you plan on going to the store.

Text and photos: Hideaki Nakayama