Created for expats living in Japan

Japanese Sweet Potatoes: All You Need to Know

One of the most popular autumn flavors of Japan is sweet potato. Japanese sweet potatoes are very versatile. They can be cooked alone or infused as a flavor into other food items. They are rich, nutritious and are often seen as a symbol of autumn in Japan. Here, we will look further into Japanese sweet potatoes, the different varieties, and some simple recipes to best use their unique flavor.

There is a range of regional varieties of sweet potato available in Japan. Kagoshima is the largest producer of sweet potatoes in Japan, but other areas have cultivated more niche varieties.

For example, Murasaki Imo is purple inside and out. It is more often used as a flavoring for other dishes due to its subtle flavor. Amai Imo is a particularly sweet variety cultivated on the island of Tanegashima. These are perfect for roasting, as the high sugar content creates a honey-roasted style effect.

Sweet potato is also a key ingredient in making some of Japan's most famous alcohol, shochu. Shochu is a distilled liquor that can be made using rice, wheat, and other starches. Sweet potato shochu is one of the most popular types of shochu.


Sweet potatoes are nutritious and rich in a range of vitamins and minerals. Eating sweet potatoes regularly is a great way to improve your daily nutrition and vitamin intake. For example, sweet potatoes are high in dietary fiber, a necessary aspect for healthy digestion.

Japanese sweet potatoes are also high in vitamin C, which effectively prevents colds and relieves fatigue, both common problems during autumn. Sweet potatoes are also high in Vitamin A and Vitamin B6. They are also rich in potassium.

Sweet Potato Recipes

Here are sweet potatoes' easy-to-cook recipes however, you can also find more recipes on Free English Websites for Japanese Food Recipes.

Yaki Imo

The most common way to eat sweet potatoes in Japan is baked/roasted. These are readily available from supermarkets, specialty shops, food stalls, and even moving food trucks. However, it is also straightforward to make your own, as long as you have an oven.

This can be done by roasting the sweet potatoes (either in foil or without) for 70-90 minutes (162˚C) for a super-sweet flavor or 50-65 minutes (190˚C) for a more caramelized, crispy outside/soft inside flavor. However, with full ovens being reasonably rare in Japan, using an oven toaster is also common.

This can be done by wrapping the sweet potato in foil and rolling them in the oven toaster every 10-15 minutes for around 70-90 minutes total.

Steamed Sweet Potatoes

Some people find that baking/roasting sweet potatoes at home results in dry sweet potatoes, so they find the steaming method better to retain the moisture of the sweet potatoes.

The best method is to slice and wash the sweet potatoes ahead of time to reduce cooking time and remove excess starch. This can be quickly done using a simple steamer. They are then steamed over medium-high heat for around 15 minutes.

Daigaku Imo

For something a bit different, you could try Daigaku Imo or candied sweet potatoes. This style of sweet potato is a popular snack, especially at food stalls. This consists of deep-frying bite-sized pieces of sweet potato. They are then coated in a candy syrup of soy sauce, mirin, sugar, and water before garnishing with black sesame seeds.

Sweet potatoes are a versatile ingredient, lending themselves well to a range of stand-alone recipes and being incorporated into more complex dishes. From just these few simple recipes, you can create a range of sweet potato-based dishes.

About Dried Potatoes

Dried sweet potatoes are a great way to conveniently and deliciously get all the nutritional benefits of Japanese sweet potatoes without cooking. Dried sweet potatoes, or Hoshi Imo, are a popular snack, especially for those trying to avoid the candy aisle. With the rich, creamy, nutty flavor intact, dried sweet potato provides a healthy, seasonal alternative to unhealthy sweets. Dried sweet potato is rich in dietary fiber as well as a range of vitamins and minerals.

Ibaraki Prefecture is the largest producer of dried sweet potatoes due to the chilly winds blowing through, traditionally used as a critical step in drying the sweet potato. While the dried sweet potato can be eaten raw, it can also be toasted to help bring out the nutty aroma and provide a sweeter and softer texture.

Preservation Method

Storing and preserving Japanese sweet potatoes should be done in a similar way to regular potatoes. Being too cold can lead to damage, so they should be kept out of the fridge. Instead, they should be kept in a cool, dark, and dry place. Wrapping in a newspaper can also help. The ideal temperature for them to be kept at is 10˚-15˚C, with temperatures over 18˚C potentially leading to germination. If the sweet potatoes are kept in perfect conditions, they can last for a long time.

Sweet potatoes can also be frozen if necessary. When choosing this method, it is essential to heat or cook the sweet potatoes first. At the very least, they should be heated in the microwave or steamer, then wrapped tightly before being frozen. This allows the sweet potato to be kept as an ingredient.

It is also possible to keep baked sweet potatoes in the freezer. This is done by following the baking process first, then wrapping tightly before keeping it in the freezer. They should then be reheated and should have the same texture and taste.


Seasonal flavors are a staple of Japanese cuisine, and sweet potato is one of autumn's most popular seasonal flavors. Japanese sweet potatoes are extremely popular among all demographics with a rich, sweet, and nutty taste, high nutritional value, and soft, creamy texture. Whether it is the ubiquitous baked sweet potato, a more snack-based candied or dried version, or a sweet potato-based meal, it is an ever-common sight during autumn.

If you are interested in learning more about food and health, please visit "Health-Food" page.

Buying Sweet Potatoes Online

You can order these sweet potatoes and dried sweet potatoes online via Amazon Japan. Click the images to find out more details.