Onsen manju are steamed buns sold as a classic souvenir in Japanese onsen towns. They are usually small and round, with a brown skin and sweet bean paste inside, and are widely found in wagashi shops in onsen districts, souvenir stores near stations, and ryokan gift shops. Although the name includes the word onsen, they do not actually contain onsen water. They became known as a specialty of onsen towns and took root nationwide as a souvenir of onsen trips, which is how they came to be called by this name.

To put it simply, onsen manju are a culture of brown steamed buns that grew up in onsen towns. That reddish-brown skin is said to have begun at Ikaho Onsen in Gunma Prefecture, where it was made to resemble the color of yunohana (mineral flakes: the minerals in the water that settle out and harden), and dark brown sugar (kokuto) is said to have been used to create that color. The buns from the shop credited as the originator became known across Japan in the Showa era, and as similar brown buns were made at onsen towns everywhere, the name onsen manju became common. That is the background to the story.

This article covers the basics of onsen manju, the reason for the brown skin and the story of how they began, regional variations, and how to buy them in onsen towns. Please note that this article explains souvenirs and food culture, and does not discuss health or beauty benefits.

What Is Onsen Manju?

Onsen manju are a type of steamed bun made by wrapping bean paste in a dough of wheat flour or similar ingredients and then steaming it. They are generally small and round, with a skin ranging from light brown to dark brown, and most have smooth or chunky red bean paste in the center. They are usually just one or two bites in size, making them easy to eat while walking through an onsen town.

They are sold in two main forms. One is a boxed souvenir version, individually wrapped for sharing with coworkers or family. The other is sold one at a time, and many shops steam them right at the storefront and sell them hot. The sight of them being sold amid the steam rising from bamboo steamers (seiro) has become one of the classic scenes of onsen towns. Freshly steamed buns have softer skins and a fuller aroma, which makes eating them on the spot part of the appeal.

In terms of taste, the skin has a gentle sweetness and a lightly toasty aroma, while many shops keep the filling only mildly sweet. They pair well with green tea and are easy for people of all ages to enjoy, which is one reason they have long been accepted as a souvenir.

The Reason for the Brown Skin and the Origin Story

What defines onsen manju is that reddish-brown skin. That color is said to have an origin.

The most widely known origin theory links them to the Yunohana Manju of Shogetsudo in Ikaho Onsen, Gunma Prefecture. According to the shop’s company history and other sources, in 1910 the first-generation owner, Katsuzo Handa, was encouraged to create a distinctive bun resembling the color of Ikaho’s onsen water, and Handa devised the reddish-brown Yunohana Manju. Ikaho’s onsen water is known for its iron content and reddish-brown tinge, and the attempt to recreate the color of its mineral flakes is said to be where the brown skin began.

Dark brown sugar (kokuto) was used as the coloring ingredient. At first, there were attempts to use the source water or the mineral flakes themselves in the dough, but they did not give good results, so kokuto, which had become easier to obtain at the time, was used to create the reddish-brown color. In other words, the account handed down at the shop credited as the originator is not that “the bun is brown because it contains onsen minerals,” but that “the color of the onsen water was expressed with dark brown sugar.” Even today, many onsen manju use kokuto or raw cane sugar to give the skin its color and flavor.

As for how they spread nationwide, the event usually cited is the Imperial Army’s special grand maneuvers held mainly in Gunma Prefecture in 1934. It is said that Gunma Prefecture presented Yunohana Manju to Emperor Showa during his visit, and that word of mouth and newspaper coverage made them known across Japan. After that, brown steamed buns began to be made in onsen towns all over the country, and the name onsen manju took hold. That is the commonly told story. However, there are several theories, and the dates and details include elements of legend, so none of this can be stated as certain.

Types and Regional Character

Even though they are all called onsen manju, the ingredients of the skin, the type of bean paste, and the method of making them vary considerably by region and by shop. The main types can be summarized as follows.

In actual onsen towns, these differences show up as the character of each place. For example, in Kusatsu Onsen, long-established shops are said to have sold steamed buns since early times, with a light brown skin as their hallmark. In Ikaho, said to be the birthplace, shops are known for pairing a kokuto skin with smooth bean paste made from Hokkaido azuki beans. In many areas, several shops in the same onsen town sell manju, so you can compare the darkness of the skin, the sweetness of the filling, and whether they are served freshly steamed.

Onsen manju may sometimes look little different from ordinary steamed buns. The difference lies in the fact that they developed as a standard souvenir of onsen towns, and that many of them inherit the line of brown skins inspired by the color of the onsen water. Rather than treating them as a completely separate kind of sweet, it is more natural to understand them as a manju culture nurtured by onsen towns.

How to Buy and Choose Them in Onsen Towns

Onsen manju are often bought as souvenirs that bring home the memory of an onsen trip. If it is your first time buying them, it helps to think separately about the ones you will eat on the spot and the ones you will take home.

If a shop sells them freshly steamed, try buying one first and tasting it. The softness of the skin and the aroma of kokuto are easiest to appreciate when they are freshly made. If you like them, then buy a boxed set to take home; in that order it is easier to match your own taste. When choosing, compare three points: the color and aroma of the skin (shops that use a lot of kokuto have darker skins), the type of filling (smooth or chunky bean paste), and the best-before date. Because steamed buns often do not keep for long, take into account the day you return home and how long you will be carrying them.

Onsen manju are also enjoyed as a light sweet treat after an onsen or sauna session. What to eat and drink after bathing is covered in Food and Hydration After Onsen and Sauna. If you also read How to Make Onsen Tamago and the Science Behind It, another food that carries the word onsen in its name, you will see how broad the food culture of onsen towns is. If you want to visit an onsen town for its onsen manju, you can find where to go in our list of places.

Frequently Asked Questions

Do onsen manju contain onsen water?

Generally, no. They do not contain the onsen water itself. They are steamed buns that became popular as a specialty of onsen towns, and the name is said to come from their becoming established as “the manju sold in onsen towns.” At the shop credited as the originator, there are said to have been attempts to use the source water in the dough while trying to recreate the color of the water, but most today make the brown skin with kokuto or similar ingredients.

Why is the skin brown?

It is said to have begun as an imitation of the color of the mineral flakes at Ikaho Onsen, said to be the birthplace (a reddish brown from the iron in the water), and kokuto is said to have been used to create that color. Many products today still use kokuto or raw cane sugar to give the skin its color and flavor, carrying on the line of brown skins.

Where did onsen manju originate?

The widely known theory is that they began with the Yunohana Manju of Shogetsudo in Ikaho Onsen, Gunma Prefecture. They are said to have been created in 1910, but there are several theories about the date and the details, so this cannot be stated as established historical fact.

Is it better to eat them on the spot or buy them as souvenirs?

They serve different purposes. Freshly steamed buns have soft skins and a full aroma, so they are best enjoyed on the spot. If you want to share them with family or friends, a boxed souvenir is more suitable. If it is your first time, eat one first and buy a box if you like it; that way you can match your own taste and avoid disappointment.

Where can you buy them?

They are widely sold at wagashi shops in onsen towns, souvenir stores near stations and at tourist spots, and ryokan gift shops. In well-known onsen towns, several shops carry them, and in some areas you can compare the differences in skin and filling.

Conclusion

Onsen manju are brown steamed buns that have long been loved as a classic souvenir of onsen towns. That reddish-brown skin is said to have begun at Ikaho Onsen in Gunma Prefecture, where it was made to resemble the color of the mineral flakes, and kokuto is said to have been used to create that color. The commonly told story is that the buns of the shop credited as the originator became known across Japan in the Showa era, similar brown buns were made in many places, and the name onsen manju spread.

They do not contain onsen water itself, but they carry on a skin inspired by the color of the water and have taken root as a sweet tied to memories of onsen trips. If you see them in an onsen town, try one freshly steamed first, and if you like it, choose a box to take home. Onsen manju are a staple of the food culture nurtured by Japan’s onsen towns.

Sources

• Shogetsudo: History of Shogetsudo (founding and origin of Yunohana Manju)
• Wikipedia: Onsen Manju (origin, nationwide spread, regional characteristics)
• Mynavi News: Onsen Trivia (8) 'Where is the birthplace of onsen manju?'