How to Use Shoyu: Ratios, Timing, and Which Type for Which Dish

Which Shoyu for Which Job: The Type Decision

Before ratios, get the type right. Using the wrong shoyu is not a subtle mistake — usukuchi in a teriyaki glaze will over-salt everything, and koikuchi in a clear soup will turn it dark brown. Here is the practical breakdown of all five main types and their best applications.

For a full side-by-side analysis, see Usukuchi vs Koikuchi.

Koikuchi (濃口) — the standard, all-purpose shoyu

About 90% of all Japanese soy sauce. Deep amber colour, salt level around 16%, rounded flavour with both savoury depth and mild sweetness from wheat fermentation. This is the default when a recipe says “soy sauce.”

Best for: marinades, stir-fry, ramen tare, teriyaki, yakitori, fried rice, dipping sauces, and any dish where the brown colour is welcome or irrelevant.

Usukuchi (薄口) — light-coloured, saltier

Paler appearance, but do not be deceived: usukuchi is saltier than koikuchi — roughly 19% sodium versus 16%. It was developed in the Kansai region for dishes where preserving the natural colour of ingredients matters.

Best for: dashi-based dishes (chawanmushi, clear soups), light-coloured nimono, pale rice dishes, Kyoto-style cooking. Use 20–25% less by volume than koikuchi to avoid over-salting.

Tamari (たまり) — thick, low-wheat, for sashimi

Made primarily from soybeans with little or no wheat. Thicker consistency, deeper and more intense flavour, lower in volatile aromatics. The traditional dipping sauce for sashimi and sushi. Also the standard choice for anyone avoiding gluten — check the label, as wheat levels vary by brand.

Best for: sashimi dipping, glazes, senbei (rice crackers). For a full guide, see What Is Tamari.

Shiro (白) — the palest shoyu, Kyoto kaiseki

Made with a high proportion of wheat and minimal soy, shiro is the lightest-coloured of all. The flavour is delicate and slightly sweet, almost wine-like. Used in high-end Kyoto kaiseki to season dishes without introducing any colour.

Best for: delicate clear broths, pale chawanmushi, finishing white sauces. Rarely found outside specialist Japanese grocers.

Saishikomi (再仕込み) — twice-brewed, the deepest flavour

Standard koikuchi is brewed with brine. Saishikomi is brewed a second time using already-finished soy sauce in place of the brine — producing a dramatically deeper, more viscous product with intense umami. Expensive and often found in premium restaurants.

Best for: sashimi dipping at premium restaurants, as a condiment rather than a cooking ingredient. The flavour is too intense for most cooked applications.

Seasoning Ratios for Common Dishes

These are the working ratios used in Japanese home and professional cooking. Memorise the nimono base (2:2:1 soy:mirin:sugar per 400ml dashi) and the fried rice rule (1 tbsp per 2 portions, added at the edge) — everything else is a variation.

Miso soup

Shoyu in miso soup is optional but effective: 1–2 tsp per 400ml dashi adds background depth without making it soy-forward. Add after the miso has been dissolved, tasting as you go. Miso varies considerably in saltiness — add shoyu only if the soup tastes flat, not as a default step.

Nimono (simmered dishes)

Standard sweet-savoury base: 2 tbsp soy + 2 tbsp mirin + 1 tsp sugar per 400ml dashi. Add shoyu and mirin together at the start of simmering — the flavours need time to integrate into the broth. For fish nimono, increase to 3 tbsp soy per 400ml because fish proteins absorb seasoning more slowly than vegetables. See how to use mirin for the full nimono framework.

Tamagoyaki (Japanese rolled omelette)

1 tsp soy per 3 eggs. More than this and the omelette turns too dark and the salt competes with the egg. The shoyu here is primarily for colour — a faint golden-brown interior rather than pale yellow. Use koikuchi for the standard version, usukuchi if you want a paler result.

Fried rice (yakimeshi)

1 tbsp koikuchi per 2 portions of cooked rice. Critical technique: pour the shoyu around the edges of the pan rather than directly onto the rice. The hot metal caramelises the sugars and amino acids on contact, creating the smoky, slightly charred aroma called wok hei — this only happens when shoyu touches metal at high heat. Add in the final 30 seconds, toss once, and remove from heat immediately.

Seasoned onigiri rice

1–2 tsp per 2 cups cooked rice, mixed in while the rice is still hot. The shoyu disperses evenly as the steam carries it through the grains. This produces a lightly seasoned rice that can be eaten plain or filled — a common technique for picnic onigiri and bento rice.

Dipping Sauces

Dipping sauces are where shoyu is used raw or barely heated — the volatile aromatics are the point. Use your best-quality shoyu here, and taste it before building the sauce.

Sashimi dip

Straight koikuchi or tamari. For a softer version, thin 3:1 with dashi: 3 tbsp soy + 1 tbsp dashi. Tamari is the traditional choice for premium sashimi — the higher soy content gives a more intense, rounded dip that does not overwhelm delicate fish.

Gyoza dipping sauce

2:1 soy:rice vinegar + chili oil to taste. Standard ratio: 2 tbsp koikuchi + 1 tbsp rice vinegar + a few drops of rayu (chili sesame oil). The acid cuts through the fatty filling; the chili adds heat. Mix fresh each time — this sauce does not keep well once combined.

Cold tofu (hiyayakko)

1 tbsp koikuchi + grated ginger + sliced spring onion, poured directly over silken tofu straight from the fridge. The contrast between ice-cold tofu and room-temperature shoyu at the table is part of the dish. No cooking required.

Tempura dipping sauce (tentsuyu)

4:1:1 dashi:soy:mirin, served warm: 200ml dashi + 50ml koikuchi + 50ml mirin. Bring to a gentle simmer for 1 minute to cook off the mirin’s alcohol, then serve immediately with grated daikon on the side. The daikon is not optional — it refreshes the palate and balances the fat of each tempura piece.

Marinades with Timing

The standard Japanese marinade base is soy + mirin + sake. The proportions shift slightly by protein, and timing is non-negotiable — fish over-marinates in under 30 minutes; beef can take 6 hours. Pat everything dry before cooking: residual marinade on the surface steams instead of searing.

Reserve trick: always set aside 2–3 tbsp of marinade before adding raw protein. This reserved portion is safe to use as a finishing glaze or dipping sauce without contamination concerns.

Chicken thighs

2 tbsp soy + 1 tbsp mirin + 1 tbsp sake + 1 tsp grated ginger. Marinate 30 minutes minimum, 2 hours maximum for boneless thighs. For bone-in pieces, up to 4 hours. The mirin’s sugars help the skin brown evenly — the glaze that forms in the last 2 minutes of cooking comes from the marinade residue caramelising on the surface.

Salmon

2 tbsp soy + 1 tbsp mirin + 1 tbsp sake + 1 tsp sesame oil. 20–30 minutes maximum. Salmon over-marinates quickly — the salt starts to cure the surface and changes the texture from silky to chalky beyond the 30-minute mark. The sesame oil is added to the marinade rather than the pan, which prevents it burning at high heat.

Tofu (for grilling)

3 tbsp soy + 2 tbsp mirin + 1 tsp sugar. Press the tofu first: wrap in paper towels, place a weighted cutting board on top, and press for at least 30 minutes to remove excess moisture. Then marinate for 1 hour. Without pressing, the tofu absorbs very little marinade and falls apart on the grill.

Mushrooms

2 tbsp soy + 1 tbsp butter (melted) + 1 tsp sake. Marinate 15 minutes — mushrooms are porous and absorb quickly. The butter in the marinade produces a rich, nutty sear when the mushrooms hit a hot pan. Works especially well with king oyster and shiitake.

Tare: Concentrated Sauce Bases

Tare (タレ) is a concentrated seasoning base — the flavour anchor that defines a dish. In ramen, the tare is what distinguishes shoyu ramen from shio or miso ramen; in yakitori, the tare is the shop’s signature. All tare recipes produce more than you need for a single meal — store refrigerated in a glass jar and use over weeks.

Teriyaki tare

4 tbsp soy + 3 tbsp mirin + 2 tbsp sake + 1 tbsp sugar. Combine in a small saucepan over medium heat, bring to a gentle simmer, and reduce by one-third (about 5 minutes). The glaze is ready when it coats the back of a spoon and leaves a clean line when you draw your finger through it. Apply to protein in the final 2 minutes of cooking — the sugars go from glossy to burnt in seconds at high heat.

Yakitori tare

100ml soy + 100ml mirin + 50ml sake + 30g sugar. Combine and simmer over medium-low heat for 15 minutes, stirring occasionally, until the mixture is thick enough to coat a skewer without dripping. Cool to room temperature — it thickens further as it cools. Refrigerated, yakitori tare keeps for 2 months. Many yakitori shops add fresh batches to the same pot over years, building layers of depth from the residue of hundreds of glazings.

Ramen shoyu tare

100ml soy + 50ml mirin + 1 tbsp sake + 1 piece dried kombu (about 10cm). No heat required: steep the kombu in the soy for 30 minutes at room temperature, then add the mirin and sake and stir to combine. Remove the kombu and strain. Add 1–2 tbsp per 300ml bowl of hot ramen broth just before serving — the tare should be stirred in at the table or just before the noodles go in, not boiled into the broth. For more depth, add a small piece of dried shiitake alongside the kombu during steeping.

For the mirin side of tare construction, see how to use mirin.

Heat and Shoyu: When to Add It

This is the single most impactful technical skill in cooking with shoyu. The same ingredient behaves completely differently depending on when it enters the heat.

Off heat — for dipping sauces and dressings

Raw shoyu at its most expressive. The 300+ volatile compounds that give premium shoyu its complex aroma are all present and intact. Use this approach for tentsuyu (once the broth has cooled slightly), ponzu, dressing bases, and any application where you want the shoyu flavour to be the lead note rather than a background seasoning.

End of cooking — for stir-fry and nimono

Flavour softens slightly, colour transfers to the food, and the sharper edges of raw soy mellow into something rounder. Add in the last minute of stir-frying for this profile. In nimono, adding shoyu mid-simmer (not at the very end) gives the dish a deeper, more integrated soy character.

High heat and caramelised — for teriyaki and fried rice

The Maillard reaction between shoyu’s sugars and amino acids at high temperature produces the characteristic dark-brown colour and smoky aroma of teriyaki glaze and yakimeshi fried rice. This is a desirable transformation — but it happens in seconds. Add shoyu at very high heat only when you intend to caramelise it, and only for the final 30–60 seconds of cooking.

Never boil hard

Prolonged boiling at a rolling boil drives off all volatile aromatics and concentrates the bitter compounds. The result is a flat, harsh soy flavour without the rounded complexity. If your shoyu-seasoned broth tastes bitter, it was overboiled. The fix: add a small amount of fresh shoyu off-heat just before serving to restore the aroma.

Shoyu Substitutes and Scaling

When a recipe calls for one type of shoyu and you only have another, use these conversion rules:

• 1 tbsp koikuchi ≈ 1 tbsp tamari (richer, slightly thicker; works in most applications)
• 1 tbsp koikuchi ≈ ¾ tbsp usukuchi (usukuchi is saltier — reduce by 25% to avoid over-seasoning)
• Western recipes calling for “soy sauce”: koikuchi works 1:1; use a light hand in the first attempt and adjust upward
• Gluten-free swap: tamari 1:1 for koikuchi in any application; for the full comparison, see What Is Tamari

The one substitution that does not work is using saishikomi (twice-brewed) as a 1:1 replacement in cooking — it is far more concentrated and will over-season any dish formulated for standard koikuchi.

Storage and Freshness

Shoyu oxidises after opening. The colour darkens, the aroma flattens, and the complex volatile compounds degrade. The practical rules:

• Unopened: 2–3 years at room temperature, away from light
• Opened, refrigerated: peak quality for 1–3 months; usable for up to 6 months
• Opened, room temperature: noticeable degradation within 2 weeks; acceptable for cooked applications only after 1 month
• Premium shoyu (especially saishikomi and artisan hon-jozo): refrigerate immediately after opening — the more complex the flavour, the more it loses at room temperature

Darkened shoyu that smells flat is still safe for cooking — the concentration of Maillard compounds gives it a deeper caramelised profile that works in braises and tare. It is no longer ideal for dipping, finishing, or dressings where fresh aroma matters.

Bottle size guidance: if you cook Japanese food weekly, the 1-litre bottle is the best value — you will use it within the quality window. For occasional use, buy 500ml or smaller. Never pour unused shoyu back into the bottle; this introduces contaminants and accelerates spoilage.

Shop premium koikuchi shoyu (Yamasa, Kikkoman Marudaizu) on Amazon →

Frequently asked questions

What is shoyu?

Shoyu (醤油) is Japanese soy sauce — a fermented condiment made from soybeans, wheat, salt, and water. The mixture is inoculated with Aspergillus oryzae (koji mold), fermented for several months, then pressed to produce the liquid. Shoyu is not a single product: there are five main types, each with different colour, salt level, and flavour profile. The most common — koikuchi — accounts for roughly 90% of Japanese soy sauce consumption and is what most recipes mean when they say "soy sauce." For a complete overview of types and production, see the companion guide on what is shoyu.

What is the difference between shoyu and soy sauce?

Shoyu is the Japanese word for soy sauce, and the terms are often used interchangeably. In practice, "shoyu" typically refers to Japanese-style soy sauce (which contains wheat), while Chinese soy sauces are made from soy alone or with different ratios. Japanese koikuchi shoyu has a rounder, more complex flavour than most Chinese soy sauces because the wheat fermentation produces additional aromatic compounds — particularly pyrazines — that contribute nutty, toasted notes. For most Japanese recipes, a hon-jozo (naturally brewed) Japanese shoyu is the right choice.

When do you add shoyu when cooking?

It depends on what you want from it. Add shoyu off-heat or at the table when you want maximum aroma — the 300+ volatile compounds are most expressive when not heat-degraded. Add it in the last minute of stir-frying for colour and mild caramelisation without bitterness. Add it at the start of simmered dishes (nimono) if you want colour and depth baked into the broth. Never boil shoyu hard for an extended period — prolonged boiling makes it bitter and flat, and drives off the aromatic compounds entirely.

Can I use shoyu instead of regular soy sauce?

Yes. Japanese koikuchi shoyu works as a 1:1 replacement for "soy sauce" in virtually any recipe. The flavour is slightly rounder and less sharp than Chinese light soy sauce, which some find preferable. For recipes calling specifically for dark soy sauce (Chinese thick soy), koikuchi is lighter — you may need to adjust quantities or cooking time to achieve the same depth of colour.

What is usukuchi shoyu used for?

Usukuchi (薄口) is a light-coloured soy sauce that is actually saltier than koikuchi — approximately 19% sodium versus 16% for standard dark soy. It is used in dishes where you want the seasoning of soy sauce without darkening the ingredients: clear soups (suimono), chawanmushi (egg custard), light-coloured nimono, and pale dishes from Kansai cuisine. Because it is saltier, use about 20–25% less usukuchi by volume than the koikuchi quantity a recipe calls for.

How much shoyu should I use?

For a main dish component (stir-fry, simmered dish): 1–1.5 tablespoons per portion. For a finishing drizzle or seasoning: 1–2 teaspoons per portion. For a dipping dish: 2–3 tablespoons. For fried rice: 1 tablespoon per 2 cups cooked rice. Shoyu contains roughly 900mg sodium per tablespoon — start conservatively and adjust upward. You can always add more salt; you cannot remove it.

Does shoyu go bad?

Shoyu does not spoil in the sense of becoming unsafe, but it degrades significantly after opening. Exposure to air triggers oxidation: colour darkens, aroma goes flat, and the complex volatile compounds break down. Refrigerate immediately after opening. At room temperature, noticeable degradation begins within 2 weeks. Refrigerated, shoyu holds peak quality for about 1–3 months and remains usable for up to 6 months. Unopened, most commercial shoyu is stable for 2–3 years.

What is the best shoyu for beginners?

Start with a hon-jozo (naturally brewed) koikuchi shoyu. Yamasa and Kikkoman Marudaizu are reliable, widely available options. Avoid bottles labelled "non-brewed" or "hydrolyzed" — these are chemically produced and lack the aroma complexity of fermented shoyu. Once you are comfortable, add a bottle of usukuchi for clear soups and delicate egg dishes. Tamari is worth having as a third option if you cook for anyone gluten-free.

Where to go next

• What Is Shoyu? — types, production process, and grades
• Usukuchi vs Koikuchi — the practical type comparison
• What Is Tamari? — the gluten-free alternative with different flavour
• What Is Mirin? — shoyu’s pairing in teriyaki, nimono, and tare
• How to Use Mirin — the full mirin ratio guide, including nimono and tare
• What Is Dashi? — the broth base for tentsuyu and simmered dishes
• Japanese Pantry — how shoyu fits into the full ingredient system
• Guides Hub — all ingredient and technique guides