Yakiimo: Roasted Sweet Potatoes

Hot, honey-sweet and wrapped in paper, yakiimo is Japan's cozy cold-weather street snack; here is its history, varieties and how to find it.

Published October 16, 2026 at 12:16 AM JST | By Tokyo Paul

Quick answer: Yakiimo, roasted sweet potato, is Japan's cozy autumn and winter street snack, traditionally stone-roasted and sold from trucks with a musical call. The slow heat turns starch into honey-like sweetness. Visitors can find it at supermarkets, convenience stores, food halls and specialty shops, and eat it wrapped in paper.

A Warm Snack With a Singsong Call

On a chilly evening in Japan, you might hear a sound that makes people smile: a long, drawn-out, musical call of "ishi-yaki-imo," drifting down the street from a slow-moving truck. The call advertises yakiimo, sweet potatoes roasted until their skins crinkle and their insides turn soft, golden and syrupy. For many people, it is the sound and smell of autumn and winter.

This guide explains the history of yakiimo, how it is cooked, which sweet potato varieties are loved, and how visitors can find and enjoy it. It is a simple food with a surprisingly rich story, and one of the most comforting treats you can pick up on a Japanese street or in a convenience store.

How Sweet Potatoes Came to Japan

Sweet potatoes arrived in the Ryukyu Kingdom, today's Okinawa, in the early seventeenth century and spread across the country over the following decades. They were valued as a hardy crop that could grow in poor soil and help people through years when rice harvests were poor. In Japanese, the sweet potato is known as satsuma-imo, a name connected with the southern region where cultivation became established.

A scholar named Aoki Konyo played an important role in popularizing the crop. The Tokugawa government supported and published a translation of his research on sweet potato cultivation to encourage wider planting, and sweet potatoes were even grown in the private garden of the shogun Tokugawa Yoshimune. By the eighteenth century, they were cultivated as a reliable crop in many regions.

Once people discovered how delicious they were when roasted, yakiimo took off. A nutritious, filling and tasty food, it became a beloved street snack. Early methods included roasting in earthenware pots or ovens, and the practice of selling roasted sweet potatoes in the cold months took hold in towns and cities.

After the Second World War, stone-roasting became the most common method. Sellers pushed carts holding iron stoves filled with heated stones, and the sweet potatoes nestled among them, roasting slowly and evenly. Each vendor had a distinctive tuneful call, and many worked the streets until the 1970s. The warm smoky aroma and the call were part of winter life.

Today, small trucks continue the tradition. They drive slowly through neighborhoods, playing a recorded version of the old peddler's voice, and the sweet scent often follows behind. People step out of their homes, buy a hot potato wrapped in paper, and eat it on the spot. The tradition is a good example of how food, sound and community come together.

The stone-roasting method is also why the potatoes are so sweet. Slow, gentle heat gives enzymes in the potato time to turn starch into sugar, producing a caramelized, honey-like flavor. The skin becomes thin and slightly wrinkled, while the inside turns creamy and fluffy.

Varieties and Flavors

Not all sweet potatoes taste the same. Japan grows many varieties, bred for differences in sweetness, color and texture. Beniharuka, for example, is known for its sticky, rich texture and honey-like sweetness when roasted. Silk Sweet is lighter and fluffier, with a more subtle sweetness. Others have bright orange flesh, golden yellow flesh or a deep purple color, and each can be roasted in a different style.

The two broad types are the yellow-fleshed Japanese sweet potato and the purple-fleshed Okinawan type, which is called beni-imo. Some people prefer a moist, almost custard-like potato, while others like a drier, flaky version that feels like a baked chestnut. Experimenting with varieties is part of the fun, and shops often explain the differences on small signs.

Specialty shops have developed all kinds of creative ways to serve them. Roasted sweet potatoes can be topped with ice cream, butter or cream cheese, and they appear in puddings, frozen shakes, shaved ice and salads. A chilled yakiimo, kept in the refrigerator, takes on a dense, creamy texture that some people love as much as a hot one.

Where to Find Yakiimo

Yakiimo is traditionally a winter food, though its season now begins in autumn, when fresh sweet potatoes are harvested and appear in markets. In recent years, its availability has expanded, and some places sell it year-round. The classic way to find it is to listen for a truck with the familiar call, but you can also look for it in other places.

Supermarkets and convenience stores often roast sweet potatoes in special in-store electric ovens, and the smell near the entrance is hard to resist. Department store food halls and street food stalls in tourist areas also sell them, and dedicated roasted sweet potato shops have become popular in many cities. Home cooks can use portable roasters, ovens or even microwaves.

Prices vary by size and variety, and the potatoes are usually sold by weight. A medium potato makes a satisfying snack, and a large one can be shared. If you want a recommendation, ask the staff which variety is sweetest, and you will likely get a friendly answer.

Tips for Eating Yakiimo

Yakiimo is usually sold wrapped in paper or placed in a paper bag. The skin is edible, and many people eat it along with the flesh, but you can peel it if you prefer. Break the potato in half to release steam and let it cool slightly before the first bite, since it can be very hot. A little of the sticky syrup may seep out, so keep a napkin handy.

In Japan, it is considered polite to avoid eating while walking in crowded places, so many people enjoy their yakiimo at a nearby bench or park, or take it home. If you buy one from a truck, a small cash amount is usually needed. Having some coins or small bills ready makes the purchase easy.

For a take-home idea, a roasted sweet potato makes an excellent breakfast or snack, and it pairs well with green tea or hojicha, which is roasted tea. Travelers staying in apartments can try roasting sweet potatoes in an oven at low heat for an hour or so, until they are soft and sweet.

Quick Takeaways

Yakiimo is roasted sweet potato, a comforting street food that grew from the crop's arrival in Japan in the seventeenth century. Stone-roasted potatoes sold from trucks with a musical call are part of the soundscape of the cold season, and today the snack also appears in supermarkets, convenience stores and specialty shops, with varieties like Beniharuka and Silk Sweet offering different textures.

For travelers, it is a simple, affordable, wonderfully cozy treat. Listen for the call, follow the smell, and enjoy a hot potato on a cool day. It is a small pleasure that many people in Japan associate with the start of winter.

Frequently Asked Questions

What is yakiimo?

Yakiimo is sweet potato roasted until the skin crinkles and the inside turns soft, golden and syrupy. In Japan the sweet potato is known as satsuma-imo. Stone-roasting became the most common method after the Second World War, and the slow, gentle heat gives the potato its caramelized, honey-like flavor.

Where can you buy yakiimo in Japan?

Yakiimo is sold from small trucks that drive through neighborhoods playing a recorded peddler's call. Supermarkets and convenience stores often roast sweet potatoes in in-store ovens, and department store food halls, tourist-area street stalls and dedicated roasted sweet potato shops sell them too. They are usually sold by weight.

What are the best varieties and how do you eat them?

Beniharuka is known for a sticky, rich texture and honey-like sweetness, while Silk Sweet is lighter and fluffier. Yakiimo is sold wrapped in paper. The skin is edible. Break the potato in half to release steam and let it cool slightly before the first bite, since it can be very hot.

Keep Exploring

More guides from Tokyo Paul: Persimmons: Japan's Golden Autumn Fruit, Hojicha and Genmaicha: Roasted and Toasty Teas, Autumn Mushrooms and Matsutake Season.