Imoni: Taro and Beef in Soy Broth, Yamagata's Autumn Pot
Taro soft all the way through, konnyaku torn by hand, beef cooked through in a sweet-savory soy broth, and long scallion simmered last until it slumps. Add the soy sauce in two stages, and add the beef only after the taro is soft.
In autumn in Yamagata Prefecture, the taro harvest comes in, and families and friends carry it down to the riverbank to gather around a big pot. This outdoor gathering is called an imoni-kai, an "imoni party," and it has become an established seasonal custom from autumn into winter. In Yamagata City, the Mamigasaki riverbank is a well-known place for friends to share a pot in the autumn.
The dish at the center of all this is imoni (芋煮). It is not one fixed recipe. Even within Yamagata, the ingredients and seasoning change by area and by household. In the inland areas, the basic pot is taro, beef, konnyaku and long scallion in a soy sauce broth; on the Sea of Japan side, in Shonai, pork and miso are the standard.
This article follows one recipe for the inland beef-and-soy style, published by Japan's Ministry of Agriculture, Forestry and Fisheries (MAFF) with the recipe provided by Yamagata Prefecture. It makes 4–5 servings in large bowls, and it is meant for an ordinary home pot rather than a riverbank cauldron. Other versions, including Yamagata City's and Nakayama Town's, are described later only for comparison; their amounts and methods are not mixed in. This recipe has not been kitchen-tested by Sekai Gohan. For more dishes from the same country, see our Japan page.
Which Imoni This Is: The Inland Beef-and-Soy Style
The MAFF page describes imoni as varying across Yamagata. Inland, the basic version uses taro, beef, konnyaku and long scallion seasoned with soy sauce. In Shonai, on the coast, pork and miso are typical. In the Mogami area, some households and areas add wild mountain vegetables or mushrooms; in the Okitama area, there are versions with large pieces of firm tofu or a little miso as a hidden seasoning.
This recipe stays with the inland style and with one set of amounts. The structure is simple: taro and konnyaku start in plain water, a first spoonful of soy sauce goes in once it comes to a light boil, and only when the taro is soft do the beef and the rest of the seasoning follow. The scallion comes last and is cooked until very soft. There is no oil, no stock and no salt; the beef fat, soy sauce, sugar and sake make the broth.
| Area (as described by MAFF) | Typical features | In this article |
|---|---|---|
| Inland Yamagata | Taro, beef, konnyaku, long scallion; soy sauce | The recipe below |
| Shonai (Sea of Japan side) | Pork and miso | Regional difference only |
| Mogami | Wild mountain vegetables or mushrooms added | Regional difference only |
| Okitama | Large pieces of firm tofu, or miso as a hidden seasoning | Regional difference only |
Ingredients: 4–5 Large Bowls, Inland Yamagata Style
Equipment
- A cooking pot large enough to hold 800cc water with the taro, konnyaku and beef
- A knife or peeler for the taro
- A knife
- A cutting board for vegetables, and a separate cutting board for raw beef
- A bowl for the torn konnyaku and cut taro
- A ladle for skimming and serving
- Chopsticks for checking the taro
- A food thermometer for checking the beef
- Large bowls (donburi or large soup bowls) for serving
Choosing and Swapping Ingredients
Taro. Pre-peeled taro, sold in Japan as arai-satoimo, lets you skip the peeling step. The 500g in the table is a skin-on weight, so it is not the same as 500g of peeled taro; adjust the amount by eye rather than by a fixed conversion.
Konnyaku. Slab konnyaku is made either from konjac flour (seiko) or from fresh konjac corm (namaimo). Check the label. Konjac-flour konnyaku can go into the pot without parboiling, which is the version used here. Konnyaku made from fresh konjac corm needs to be boiled and drained (yudekoboshi) before it goes in.
Beef. Fatty cuts such as thin-sliced belly or fatty trimmings give the broth its richness. Lean thin slices also cook, but the broth will be lighter in body. Switching to pork is not a substitute within this recipe: pork with miso is the Shonai style, a different regional pot.
Sake. Use ordinary drinking sake (seishu). Japanese cooking sake (ryōrishu) often contains salt and other additions, so if you use it, taste before adding more soy sauce.
Soy sauce and sugar. Keep to the tablespoon amounts and the two-stage soy addition. Soy sauces differ, so taste at the end rather than adding extra up front.
This dish contains beef and soy (soy sauce). Many soy sauces also contain wheat; check the product label. Handle raw beef on its own board, and wash your hands and any tools that touched raw beef before handling the vegetables or serving bowls.
Method: Taro First, Beef Second, Scallion Last
The first five steps are preparation. From step 6 on, the order is fixed: water, then taro and konnyaku, then heat, 1 tbsp soy sauce, soft taro, beef, the remaining seasoning, skimming, and the scallion last.
No cooking times are given below. The time it takes depends on your pot, your heat and the size of the taro, so judge each stage by its state: taro that a chopstick goes into easily, beef cooked through, scallion very soft.
Japan's Ministry of Health, Labour and Welfare (MHLW) gives heating food until the center reaches 75°C for at least 1 minute as a general guide. This is general food-safety guidance, not a time or stage from the imoni recipe, and the look of the pot or a photograph cannot show that it has been reached. If you need to pause partway through cooking, refrigerate the pot, and when you resume, reheat it thoroughly.
Serving: One Big Bowl Each
Inland imoni is served in a big bowl with plenty of broth: soft taro, beef, torn konnyaku and scallion cooked until very soft. It needs no garnish. Shichimi is an optional table seasoning; add it to your own bowl if you like, rather than to the whole pot.
Leftovers and Reheating
Divide leftover imoni into shallow containers so it cools quickly, and do not leave it at room temperature for a long time. Refrigerate it once cooled, covered. Reheat it thoroughly before eating. No number of storage days is set here, so use your judgment and do not keep it long.
Hard Taro, Rubbery Konnyaku, Salty Broth: Fixing Problems in the Pot
| Problem | Likely cause | What to do |
|---|---|---|
| Taro still firm when the beef is in | Beef added before the taro was soft, or pieces cut unevenly | Keep simmering and check the largest piece with a chopstick. Next time, wait for soft taro before adding the beef |
| Some taro soft, some firm | Pieces of very different sizes | Keep simmering until the largest piece is soft. Cut pieces more evenly next time |
| Konnyaku has a strong smell or odd texture | Fresh-potato konnyaku used without parboiling | Check the label next time; boil and drain fresh-potato konnyaku before adding it |
| Konnyaku pieces look smooth and slip around | Cut with a knife instead of torn | Tear by hand next time; rough edges hold the broth |
| Broth too salty | All the soy sauce added at once, or salted cooking sake used | Add the soy sauce in two parts as written, and taste before adding more. With cooking sake, be careful with soy sauce |
| Broth thin and lacking richness | Lean beef | Use fatty thin-sliced beef such as belly or trimmings |
| Scallion still crisp | Not simmered long enough after adding it | Keep simmering until it is very soft |
| Unsure the beef is cooked | Thick folded pieces | Check the thickest piece with a thermometer; 75°C at the center for at least 1 minute is the general guide |
Regional Variations: Other Pots, Not Additions to This One
Each of these is a different version of imoni, not a tweak to the recipe above. If you want to try one, treat it as its own pot.
- Shonai style: Pork in place of beef and miso in place of soy sauce. This is the standard on the Sea of Japan side of Yamagata.
- Mogami style: Some households and areas add wild mountain vegetables or mushrooms.
- Okitama style: Some versions use large pieces of firm tofu, or a little miso as a hidden seasoning.
- Udon at the end: When the pot has run low, udon noodles can be added to the remaining broth. This is a way of finishing the pot, not something to put in from the start.
- Curry roux: A more recent way to eat leftovers is to add curry roux to what remains. It is a second dish made from the leftovers, not an ingredient of imoni itself.
Culture and History: Riverbanks, Boatmen and Beef
According to MAFF, the imoni-kai is a custom of autumn into winter: people bring taro from the harvest to the riverbank and share a pot with family and friends. Yamagata City likewise describes friends gathering around pots on the Mamigasaki riverbank in autumn.
On origins, MAFF introduces a theory that the custom dates to the mid-1600s, and a story of boatmen working the Mogami River gathering around a pot on the riverbank. These are presented as traditions and accounts, not as established historical fact, and this article treats them the same way. MAFF also notes that beef is said to have come into use around the early Showa era; this, too, is a commonly told account rather than a documented date.
Yamagata City and Nakayama Town each publish their own beef-and-soy imoni recipes. They use different amounts and steps, such as rubbing the taro with salt to remove its sliminess or parboiling the konnyaku, and Nakayama Town's current recipe is written for 4 servings. Those recipes are separate from the one in this article and are not combined with it. Nakayama Town also distinguishes its imobōni, a dish of taro with dried cod (bōdara), from the beef imoni that is common today. It belongs to the area's imoni culture but is a different dish.
Frequently Asked Questions
Is Yamagata imoni flavored with miso or soy sauce?
Both, depending on where you are. In inland Yamagata, beef and soy sauce are typical; in Shonai, on the coast, pork and miso are typical. This recipe is the inland beef-and-soy style.
Do I need to parboil the taro?
No. In this recipe, the cut taro goes straight into the pot with the water and konnyaku. Some other recipes, such as Yamagata City's, rub the taro with salt to remove sliminess, but that is a different method and is not part of this one.
Does the konnyaku need parboiling?
It depends on how it is made. The MAFF recipe separates the two: konjac-flour konnyaku can skip parboiling, while konnyaku made from fresh konjac corm should be boiled and drained first. Check the label on the pack.
When does the beef go in?
After the taro is soft. Adding the beef together with the remaining seasoning at that point is the order MAFF's recipe gives. The chopstick check is a practical way to judge softness; the recipe does not give a time in minutes for it.
How long does it take to cook?
The recipe gives no cooking times or temperatures for the stages. It depends on your pot, your heat and the size of the taro, so cook by the state of the pot: soft taro, beef cooked through, very soft scallion. The 75°C-for-1-minute figure for the beef is general food-safety guidance from MHLW, separate from the recipe.
What do I serve with it?
Shichimi at the table is optional. Udon added to the leftover broth and curry roux added to leftovers are ways of eating that MAFF mentions, but they are not part of the basic recipe.
Sources
- Ministry of Agriculture, Forestry and Fisheries (recipe provided by Yamagata Prefecture), "芋煮 山形県 | うちの郷土料理" (Imoni, Yamagata Prefecture | Our Local Cuisine). The recipe in this article: ingredients, amounts, 4–5 servings, order of steps, the taro and konnyaku options, regional differences within Yamagata, the imoni-kai custom, and the origin accounts presented as tradition. https://www.maff.go.jp/j/keikaku/syokubunka/k_ryouri/search_menu/menu/imoni_yamagata.html
- Yamagata City Official Website, "いも煮" (Imoni). Used only for comparison: the city's separate recipe and the autumn custom of gathering around pots on the Mamigasaki riverbank. Its amounts and steps are not used in this recipe. https://www.city.yamagata-yamagata.lg.jp/kenkofukushi/iryou/shokuiku/1003317/1007212/1003301.html
- Nakayama Town, Yamagata (Nakayama Town Tourism Association), "牛肉の芋煮の作り方" (How to Make Beef Imoni). Used only for comparison: the town's separate 4-serving recipe and the distinction between imobōni and beef imoni. Its amounts and steps are not used in this recipe. https://www.town.nakayama.yamagata.jp/soshiki/nakayama_kanko/322.html
- Ministry of Health, Labour and Welfare, "腸管出血性大腸菌Q&A" (Enterohemorrhagic E. coli Q&A). General guidance on heating food to 75°C at the center for at least 1 minute, refrigerating when cooking is interrupted and reheating thoroughly, and cooling leftovers in shallow containers and reheating them. Not a source for the imoni recipe itself. https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/0000177609.html
