Daigaku Imo (大学芋, daigaku imo) is a Japanese sweet potato snack made by frying bite-sized pieces and coating them in sugar syrup, usually with black sesame seeds. Imo means potato or tuber in Japanese. “University potato” is the literal translation, while Japanese candied sweet potatoes is the clearer descriptive name in English.
The strange name is only half the story. The coating can be soft and glossy, or thin and glass-like, and the two styles eat very differently. This guide explains the name, the history, the best sweet potato varieties, a home recipe, and where to find it in Tokyo.
What is Daigaku Imo?
In short, it is a Japanese sweet potato dessert of fried, skin-on chunks tossed in hot syrup. Often, a splash of soy sauce rounds out the sweetness, and black sesame finishes it.
Quick answer
- What does it taste like? Sweet and caramel-like, with a faint salty note from soy sauce and nuttiness from black sesame.
- Where can I try it? Asakusa in Tokyo has specialty shops within a short walk of Sensoji temple.
- Is it vegan? The basic sugar, soy sauce, oil, sesame, and sweet potato version generally uses no animal-derived ingredients. Versions made with honey are not vegan.
Quick facts
- Japanese name
- 大学芋 (daigaku imo)
- Literal meaning
- “University potato”
- Descriptive English name
- Japanese candied sweet potatoes
- Name origin
- Several theories, none confirmed
- Closely linked place
- Tokyo, especially Asakusa and old student districts
- Served
- Warm or at room temperature; sold year-round at specialty shops
Choose what you need
What does Daigaku Imo taste like?
Daigaku Imo combines the natural, chestnut-like sweetness of Japanese sweet potato with a caramel-scented sugar coating. A small amount of soy sauce adds a faint salty note that keeps the sweetness from tasting flat. Black sesame, meanwhile, brings a toasted, nutty finish.
Texture depends on the glaze. A soft syrup makes the surface glossy and slightly chewy, whereas a more concentrated candy coating cools into a thin, crisp shell. Inside, the potato may be fluffy or moist. That depends on the variety, the cut size, and how long it fried. One warning, though: it is more filling than it looks.
Want to taste it before you cook it? Asakusa is the easiest place, and the Tokyo shop section below lists two specialists.
Why is it called university potato?
Daigaku Imo has no single confirmed name origin. Theories connect it with university students who enjoyed the inexpensive snack, a sweet potato shop near a university, or students who sold it to help pay tuition. These stories remain traditions rather than conclusively documented history.
The Japan Root and Tuber Crops Research Association, a sweet potato research body, calls the name one of the great unsolved questions of the potato world. By its own account, no definitive answer exists. It does, however, relay one story from a 1996 regional newspaper. A Tokyo University student, short of money in the slump of 1927, supposedly began making and selling the snack. Even so, the association adds that nobody can prove it.
| Theory | Summary | Evidence status |
|---|---|---|
| Student customers | Cheap, filling, and sweet, so it sold well in student districts such as Kanda and Hongo. | Reported tradition |
| A shop near a university | A steamed-potato shop called Mikawaya, said to have stood near the University of Tokyo’s Akamon gate, sold glazed fried potato. | Unverified anecdote |
| Students selling it | A student made and sold it around 1927 to cover tuition, as relayed by the research association. | Reported tradition, unproven |
| “University” as a sales word | Attaching “university” to products was a marketing fashion of the era. | Unverified anecdote |
Which is true? These accounts share a connection with Tokyo’s university districts. However, the available sources do not establish which story explains the name.
A short history of Daigaku Imo
The snack is roughly a century old. According to the research association, it caught on after the Great Kanto Earthquake of 1923. Similarly, an industry journal places its birth between the early Taisho and early Showa eras. The sweet potato itself is far older in Japan; the agriculture ministry dates its arrival in Edo to 1734.
A similar dish exists in Chinese cooking, often written 拔絲地瓜, where fried sweet potato gets a hard sugar coating. Some Japanese writers see it as a model for Daigaku Imo. We found no primary source for that link, so we treat it as a resemblance.
Best sweet potato for Daigaku Imo
There is no single best sweet potato for Daigaku Imo, so choose by the texture you want inside. Fluffy, dry-fleshed varieties fry crisper and hold their shape. Moist, high-sugar varieties, by contrast, taste sweeter but soften faster in the pan. Japanese sweet potato varieties fall roughly into three groups.
Fluffy (hokuhoku) type
Beni Azuma, Naruto Kintoki, and Kokei No. 14 are the classic choices. Their flesh stays dry and crumbly after frying, so it gives the clearest contrast with the glaze. A 2020 crop science study grouped Beni Azuma and Kokei No. 14 as conventional varieties, in contrast to newer high-sugar types.
Sticky (nettori) type
Anno Imo, from Tanegashima in Kagoshima, is the best-known example. It is intensely sweet and almost custard-like when cooked. For this snack, though, cut it larger and fry it gently, because it collapses more easily than fluffy types.
Moist (shittori) type
Beni Haruka, Silk Sweet, and Aikomachi sit between the two. The same 2020 study linked the sweetness of newer varieties such as Beni Haruka to a low starch gelatinization temperature and high beta-amylase activity. In other words, the study helps explain why some newer varieties taste sweeter after cooking. For Daigaku Imo, simply adjust the amount of glaze to your preferred sweetness.
Cooking outside Japan
Cannot find Japanese varieties? Look for a sweet potato with purplish-red skin, pale yellow flesh, and relatively low moisture. Asian grocers often label them as Japanese or Korean sweet potatoes. Orange, high-moisture types will still work. In that case, however, the pieces turn softer and the glaze may slide off.
How to make Daigaku Imo: a reference recipe
The basic method is simple: fry the sweet potato, make a syrup, and toss the two together while both are hot. This Daigaku Imo recipe is a reference outline for the glossy-syrup style, not a tested recipe. Food in Japan has not yet cooked it in this form, so treat every time and temperature as a starting point.
Glossy syrup or crisp candy shell?
Daigaku Imo comes in two glaze styles. A glossy syrup gives a sticky finish, while a candy coating can set into a brittle shell. This outline covers the glossy style only, because it is easier to judge by eye: stop when the syrup thickens and bubbles slowly. The candy shell needs the sugar cooked further, and we will add it once we have tested it.
One rule applies to both. Do not stir hard once the syrup boils, because agitation encourages sugar crystals. Scraping dried sugar from the pan wall back into the pot does the same. For that reason, some cooks add a few drops of vinegar or lemon juice.
Ingredients and timing
Daigaku Imo, glossy-syrup style (untested reference outline)
Ingredients
- Sweet potato: 250 to 300 g (9 to 10½ oz), about 1 medium
- Neutral cooking oil for frying, such as canola or rice bran oil
- Sugar: 4 tbsp (about 50 g / 1¾ oz)
- Water: 1 tbsp
- Soy sauce: ⅓ tsp
- Black sesame seeds: 1 tsp
- Optional: a few drops of rice vinegar
Why a neutral oil? It tolerates frying heat without adding flavor. Yield is roughly 15 to 20 chunks of 3 cm.
Instructions
- Prepare. Scrub the potato and leave the skin on. Cut it into rough 3 cm (1¼ in) chunks, or 1.5 to 2 cm sticks. Soak for 5 to 10 minutes, then dry well.
- Fry. Heat 2 to 3 cm of oil to about 160 to 170°C (320 to 340°F). Fry in one layer for 6 to 8 minutes, turning once.
- Check doneness. Look for deep golden edges. A skewer should slide through the center without resistance, and the middle should no longer look chalky. Drain on a rack.
- Make the syrup. In a clean pan, warm the sugar and water over medium heat without stirring. Add the soy sauce once the sugar dissolves. Stop when the syrup thickens and bubbles slowly.
- Glaze. Add the hot potato and swirl the pan to coat. Sprinkle the sesame while the syrup is still wet.
- Cool. Spread the pieces in one layer on a silicone mat or lightly oiled baking paper. Do not pile them in a bowl, or they will fuse and the glaze will pool at the bottom.
Honey and soy sauce: two cautions
Food safety notes
Some recipes replace part of the sugar with honey. If you do, remember that honey should not be given to infants under one year old. Soy sauce often contains wheat, so this dish is not automatically gluten-free; choose a wheat-free tamari if that matters to you.
One-pan variation
Our original 2023 recipe used a one-pan shortcut. Put 5 tablespoons of oil, the sugar, the soy sauce, and the raw potato in a frying pan together over medium heat. When foam appears, lower the heat slightly. Cook for 6 to 7 minutes, turning the pieces, then reduce to low once they color. Finally, drain the oil while stirring the sugar that has collected on the pan bottom, and add sesame while hot.
This method saves a pan. However, sugar and oil heat together from the start, so watch closely for scorching. We have kept it here as a variation because it differs from the usual fry-then-glaze order.
Can you make Daigaku Imo without deep-frying?
Yes. A shallow-fried or pan-cooked version is possible, although its crust differs from deep-fried Daigaku Imo. A recipe on the agriculture ministry’s website, supplied by a farm cooperative in Tottori, cuts about 250 g of potato into 1 cm sticks. It then cooks them in just 1 tablespoon of oil until crisp, before tossing with 1 tablespoon of sugar, 1 teaspoon of soy sauce, and black sesame. In other words, the thin cut is the trick, because it gives more surface to crisp.
How to keep Daigaku Imo crispy
Crispness comes from three things: a dry surface before frying, enough heat, and fast cooling in a single layer. First, pat soaked potato completely dry, or it steams instead of fries. Second, fry in batches so the oil temperature holds. Afterward, keep the pieces apart on a mat until the glaze sets.
Be honest with your expectations, too. A glossy syrup gives a sticky finish, while a candy coating can set into a brittle shell. The texture of the fried potato itself also depends on the variety and cooking method. Either way, both styles soften in humid weather and in the refrigerator.
Storage and reheating
Homemade Daigaku Imo is best eaten soon after cooking. For Daigaku Imo storage, cool the pieces quickly, seal them in a container, and refrigerate. Then eat them within a day or two; published guidance ranges from about two days to three, so err on the early side. For shop-bought portions, the printed date and the shop’s instructions take priority over any general rule.
Reheating brings back some aroma. Either a microwave or a toaster oven can do the job, but we have not compared them side by side. So warm in short bursts and watch closely, because sugar syrup burns quickly.
Daigaku Imo vs yakiimo and similar sweets
The main difference is the coating. Yakiimo is a whole roasted sweet potato with nothing added, so its sweetness is entirely natural. Daigaku Imo is fried and glazed. The table below adds two more sweet potato snacks for comparison.
| Snack | Method | Coating | Texture | Common association or availability |
|---|---|---|---|---|
| Daigaku Imo | Fried chunks | Sugar syrup, soy sauce, sesame | Glossy and chewy, or thin and crisp | Nationwide; closely associated with Tokyo |
| Yakiimo | Roasted whole | None | Soft, fluffy or moist | Nationwide, strongest in autumn and winter |
| Imo kenpi | Fried thin sticks | Sugar glaze | Hard and crunchy | Nationwide; strongly associated with Kochi |
| Imo yokan | Steamed and pressed | None | Dense, soft block | Nationwide; closely associated with Asakusa |
How does Daigaku Imo compare with Korean candied sweet potato, goguma mattang? Both dishes combine fried sweet potato with a sweet coating. Many mattang recipes emphasize a hard candy shell, and some also use sesame seeds, so sesame alone does not distinguish the two. Soy sauce in the glaze is the more typically Japanese touch.
When is the best time to eat it?
Autumn and early winter are the obvious answer, because that is when Japanese sweet potatoes are harvested and shops push the new crop. It is not strictly a seasonal dish, though. In fact, specialty shops and deli counters sell it year-round.
Storage after harvest also plays a part. In one 2020 Japanese study, two weeks of storage raised the soluble sugars in steamed sweet potato, although results varied by variety. So “rested potatoes are sweeter” is roughly true, but not a law.
Where can you buy Daigaku Imo?
You will find it in five kinds of places: sweet potato specialty shops, department store food halls, supermarket deli corners, autumn festival stalls, and online. Specialty shops usually sell by weight, often from 200 g. So tell the counter how much you want and confirm the price first, since totals add up fast. Also, many shops are takeaway only.
Searching “Daigaku Imo near me” in a map app works in big cities. In Japan, however, typing the Japanese name, 大学芋, returns far more shops. Afterward, check the shop’s official page, because hours and days off change often.
Where to eat Daigaku Imo in Tokyo
Asakusa is the easiest place to start, because two specialty shops sit within a short walk of Sensoji temple. For a full route that includes yakiimo and imo yokan, use our Asakusa sweet potato food guide. Each card below shows when we checked the details.
Asakusa
Daigaku Imo Chibaya (大学いも 千葉屋)
Old-school specialist behind Sensoji
- Best for
- Thick-cut pieces from a long-running specialist; local media describe a short menu of daigaku imo and a thin-sliced version called kiriage
- Typical style
- Sold by weight and reported as takeaway only; bring cash in case cards are not accepted
- Address
- 3-9-10 Asakusa, Taito-ku, Tokyo (on Kototoi-dori, behind Sensoji)
- Nearest station
- Asakusa Station on the Tsukuba Express is the closest; from the Ginza Line station, allow roughly 10 to 15 minutes on foot
- Hours
- 10:00 to 18:00, closed Tuesdays, according to the Asakusa district site. Some listings show Sundays ending at 17:00, so check current days before visiting.
- Phone
- +81-3-3872-2302
- Checked
- October 2026
Oimoyasan Koshin (おいもやさん興伸)
Wholesaler-run chain with several Asakusa counters
- Best for
- Several branches around Asakusa, so it is easy to fit into a temple visit; run by Kawako Shoten, a sweet potato wholesaler founded in 1876
- Typical style
- The Nakamise shopping street page describes the daigaku imo as fried in rapeseed oil and coated in a house syrup, sold from 200 g
- Orange-dori branch
- 1-21-5 Asakusa, Taito-ku. Opens 10:00, daily. Sources list closing as 18:00 or 19:00, so confirm before a late visit. Tel +81-3-3842-8166
- Denboin-higashi-dori branch
- 1-36-6 Asakusa, Taito-ku. Listed as 9:00 to 20:00, open daily; weekend opening may be earlier. Tel +81-3-3843-3886
- Nearest station
- Asakusa (Ginza Line); both branches are a short walk, roughly 5 minutes
- Official information
- Koshin official website; check its store list before visiting, because published closing times differ
- Checked
- October 2026
Other Tokyo areas
Outside Asakusa, department store food halls are a practical place to look. In addition, Koshin’s website mentions branches at Daimaru Tokyo, next to Tokyo Station, and in Sugamo. Because branch details change, confirm them on the official page first.
Conclusion
Daigaku Imo is an easy Japanese sweet potato snack with a hard-to-pin-down name. Nobody can prove which student, shop, or sales gimmick named it, and that is part of its charm. The simplest next step is to taste one. Start with the Asakusa sweet potato guide, then decide which glaze you want to cook at home.
Daigaku Imo FAQ
Eating and buying
- Is Daigaku Imo served hot or cold?
-
Both. Freshly made, it is warm and the glaze is still soft. Shops usually sell it at room temperature, and some even suggest a brief warm-up at home. Cold from the refrigerator, the glaze firms up and the potato tastes denser.
- Is Daigaku Imo vegan?
-
Usually, yes. The standard version uses sweet potato, sugar, oil, soy sauce, and sesame, none of which are animal-derived. However, some recipes and shops use honey or butter. Ask, or read the label, if that matters to you.
- Is it the same as Korean candied sweet potato?
-
No, although they are close cousins. Many goguma mattang recipes aim for a hard candy shell, while Daigaku Imo is often glossier and faintly salty from soy sauce. Both may carry sesame seeds. See the comparison section above for more.
- How much does it cost in Tokyo?
-
It depends on the shop and the weight. Specialty shops usually sell by weight, and one Asakusa shop sells from 200 g. Prices change, so we do not quote figures here. Instead, confirm the price per 100 g at the counter before ordering.
Cooking troubleshooting
- Why did my syrup turn grainy?
-
The sugar crystallized. This usually happens when you stir hard after the syrup boils, or when dried sugar on the pan wall falls back in. Next time, swirl the pan instead of stirring. A few drops of vinegar or lemon juice also help.
- Why are my pieces soggy instead of crispy?
-
Most often, the potato was wet going into the oil, or the oil was too cool. So dry the pieces thoroughly after soaking and fry in small batches. Then cool them in a single layer, not in a bowl. A moist variety also softens faster than a fluffy one.
Preparation
- Do I have to leave the skin on?
-
No, but many recipes do. The skin helps hold the chunks together in the oil and also adds color. If you peel, cut the pieces slightly larger so they do not fall apart during glazing.
About this guide
- Originally published
- November 27, 2023
- Substantially reviewed
- October 3, 2026
- History and sources
- Food in Japan editorial team
- Recipe status
- Untested reference outline for the glossy-syrup style. We will add tested notes (variety, weights, oil temperature, syrup stage) after testing.
- Update note
- We merged the name and history sections, changed the name-origin section from a single answer to labeled theories, reorganized the recipe into a basic method plus variations, removed one Itabashi shop card whose name and hours we could not verify, and rechecked Asakusa shop hours against official and district pages.
References
- Japan Root and Tuber Crops Research Association – Q&A: Where does the name daigaku imo come from? (大学いもの名前の由来を教えて下さい) (Accessed October 2026)
- Japanese Journal of Crop Science (J-STAGE) – Nishinaka, M., Takada, A., Kuranouchi, T., Nakamura, Y., & Katayama, K. (2020). Influence of cultivation method and postharvest short-term storage on quality characteristics and high sugar content of sweetpotato varieties. 89(2), 110–118 (Accessed October 2026)
- Ministry of Agriculture, Forestry and Fisheries (MAFF) – No-fry crispy daigaku imo recipe by JA Tottori Seibu (揚げないカリカリ大学芋) (Accessed October 2026)
- Japan Root and Tuber Crops Development Association – Imo-rui Shinkō Jōhō No. 147: Daigaku imo specialty shops and the Japan Daigaku Imo Lovers Association (Accessed October 2026)
- Kawako Shoten / Oimoyasan Koshin – Official website and store list (Accessed October 2026)
- Asakusa Oideyo (official Asakusa shopping-district guide) – Daigaku Imo Chibaya shop details (Accessed October 2026)
- Asakusa Orange-dori Shopping Street Association – Oimoyasan Koshin Orange-dori shop (Accessed October 2026)
- Taito City Tourist Souvenir Association – Oimoyasan Koshin (Accessed October 2026)
Related Articles
- Asakusa Sweet Potato Food Guide: Yakiimo, Daigaku Imo, Imo Yokan and More (Surveyed: October 2026)
- Yakiimo (Surveyed: October 2026)
- Anno Imo Sweet Potato (Surveyed: October 2026)
- Imo Shochu (芋焼酎) (Surveyed: October 2026)
- Imo Yokan (芋ようかん) (Surveyed: October 2026)
- Imo Kenpi (いもけんぴ) (Surveyed: October 2026)
- Sweet Potato Cake (スイートポテト) (Surveyed: October 2026)
Comments