Tonjiru: Japanese Pork and Root Vegetable Miso Soup

Tonjiru (豚汁, "pork soup") — also read butajiru in some regions — is a Japanese miso soup built around pork. Unlike standard miso soup (misoshiru), which is a light, delicate broth with a few ingredients, tonjiru is substantial: thick with root vegetables, enriched by the pork fat, and designed to be a main component of a meal rather than a supporting bowl.

It is winter food — warming, filling, deeply savory. It appears in Japanese school lunch programs, in rural farmhouses, in restaurants that serve traditional Japanese set meals. It is also simple to make: the technique is barely more complicated than standard miso soup, but the result is many times more satisfying.

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Why Tonjiru Is Different From Miso Soup

Standard miso soup (misoshiru): clear or lightly cloudy dashi base + small amount of miso + 1-2 ingredients (wakame, tofu, daikon). Served as a side dish. Portion: 150ml.

Tonjiru: dashi base with pork fat rendered into it + substantial root vegetables simmered until soft + miso added at the end. Served as a main-ish dish or substantial side. Portion: 300-400ml.

The key difference: tonjiru is built on rendered pork fat, not just dashi. The fat gives the broth a richness and depth that makes it warming in a way a thin miso soup is not.

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Ingredients (4 servings)

Vegetables:

• 200g daikon, cut into half-moons (1.5cm thick)
• 2 medium carrots, cut into half-moons
• 100g burdock root (gobo), sliced thinly on a diagonal — soak in cold water for 5 minutes to remove bitterness
• 1 block konnyaku (konjac jelly cake), torn into rough pieces — the irregular surface absorbs more broth than clean cuts
• 1 medium potato, cut into chunks (optional — adds body)
• 3cm piece ginger, sliced

Pork:

• 200g pork belly, cut into 3-4cm pieces (thinly sliced pork, like sukiyaki pork, also works)

Broth:

• 1L dashi (kombu + katsuobushi, or instant)
• 3-4 tablespoons white miso (shiro miso) or mugi miso (barley miso) for more depth
• 1 tablespoon soy sauce
• 1 tablespoon mirin

Garnish:

• Sliced green onion
• Sesame seeds
• Shichimi togarashi (7-spice chili) — optional

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Method

1. Render the Pork

In a medium-large pot over medium heat, add the pork belly pieces with no oil (the fat renders out immediately). Cook 3-4 minutes, turning occasionally, until the edges are lightly golden and the fat has rendered into the pot.

The rendered pork fat becomes the flavor base. Do not drain it.

2. Add Aromatics and Vegetables

Add ginger to the pork fat. Cook 1 minute. Add burdock root (drained), daikon, carrots, potato (if using), and konnyaku. Stir to coat in the pork fat.

Cook over medium heat 2-3 minutes, stirring occasionally — this brief sauté in the fat before adding liquid improves the vegetable flavor.

3. Add Dashi

Pour in the dashi. Add soy sauce and mirin. Bring to a boil, then reduce to a gentle simmer. Cook 15-20 minutes until the vegetables are completely tender when tested with a chopstick. The daikon should be translucent and yielding; the burdock root chewy but cooked through.

Skim any foam that rises in the first 5 minutes.

4. Add Miso

When vegetables are done, reduce heat to very low. The broth should no longer be simmering.

Dissolve the miso paste in a small amount of the hot broth in a separate small bowl (this prevents lumps). Pour the dissolved miso back into the pot. Stir gently.

Never boil after adding miso. Boiling miso kills the live fermentation cultures and flattens the flavor. Miso is always added off or near-off heat, at the very end.

Taste. Tonjiru should be savory with a full miso presence. Adjust with more miso if needed, or a touch more soy sauce for saltiness.

5. Serve

Ladle into deep bowls. Garnish with green onion, sesame seeds, and shichimi if desired.

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The Burdock Root

Gobo (burdock root) is the ingredient that makes tonjiru distinctly Japanese. It has an earthy, slightly woody flavor — nothing else tastes like it. It is fibrous and requires the 5-minute soaking step (which removes tannins that would otherwise make the broth bitter) and full cooking time to become tender.

Substitutes if unavailable: parsnip (closest in earthiness), turnip, or simply omit. The soup will still be very good; it will be missing a specific Japanese quality.

At Asian grocery stores, gobo is sold fresh (brown, fibrous root) or pre-shredded in bags. The shredded version is convenient but not ideal for tonjiru — the larger pieces hold up better during the 20-minute simmer.

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Konnyaku (Konjac)

Konnyaku is a firm jelly made from konjac flour. It has almost no flavor of its own but absorbs the surrounding broth intensely. The texture is firm and slightly springy — unlike tofu (soft, yielding) or vegetables (soft when cooked). It is a classic tonjiru ingredient for this textural contrast.

Available at Japanese grocery stores as a block. Tear or spoon into rough pieces rather than cutting — the irregular surface creates more broth absorption surface area.

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Variations

Tanuki tonjiru: Add a tablespoon of tenkasu (tempura flakes) to each bowl just before serving. The flakes absorb the broth and add a light crunch that contrasts with the soft vegetables.

Spicy tonjiru: Add 1 tablespoon gochujang to the broth along with the miso. The Korean chili paste integrates with the Japanese miso seamlessly — both are fermented, both are savory-forward, both complement pork. This version runs right down the center of the Borderless Kitchen brand.

Mushroom tonjiru: Add 100g of mixed mushrooms (shiitake, shimeji, enoki) for more umami depth. Add at the same time as the root vegetables.