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Koikuchi
  • Soy sauce type
  • 濃口醤油

Koikuchi

The soy sauce recipes mean when they just say soy sauce.

Flavor profile

Salinitysalinity 75%
Umamiumami 70%
Fermentfermented depth 70%
Roastroasted wheat 50%

The strengths are editorial judgments on a scale within the family, not measurements. They can be compared across the soy sauce varieties, not directly against another family.

Origin the form took shape in the city kitchens of the Edo period

Koikuchi is the standard soy sauce: over 80 percent of everything brewed in Japan, and almost always what sits on a Western shelf when the label says Japanese soy sauce. Roughly equal parts soybeans and roasted wheat give a sauce that is dark but balanced, salty but round, and equal to everything from dipping dish to stew. The other four types are best understood as departures from this one.

Sensory analysis

Pyramid and character

Aroma

from the tub

  • roasted wheat
  • ferment
  • caramel

Taste

on the tongue

  • umami
  • salinity
  • round sweetness

Finish

what lingers

  • long
  • clean
  • warm
SALINITYSWEETNESSUMAMIACIDITYFERMENT DEPTHBODY

Character 0-100 per axis, set relative to the other entries in the same family. An editorial judgment of a typical serving, not measurements.

Background

Facts

Proportion
over 80 percent of Japanese production; the word means dark mouth, that is, the dark kind of soy sauce
Composition
roughly equal parts soybeans and roasted wheat, with a salt content around 18 percent
Origin
the form took shape in the city kitchens of the Edo period; Noda and Choshi in Chiba became its centers, and Chiba remains the largest producing prefecture
Use
the all-round soy sauce, for dipping, stews, glazes, and dressings; recipes that just say soy sauce mean koikuchi
Storage
takes time better than the pale types, but the aroma fades once the bottle is opened; refrigeration stretches it

In the kitchen

Use

Dosage
recipes are written for it, so dose as written; a tablespoon carries a stew for two
Timing
tolerates heat and can go into the pot early, but the top layer of aroma is perishable, and a final splash at serving does more than an early one
Note
look for the word honjozo, fully brewed, on the label; blended sauces built on hydrolyzed protein look the same in the bottle but lack the depth of brewing

Keep exploring

Related in the Zukan

Evidence

Sources

  1. Soy sauce (Wikipedia) (retrieved 2026-08-15)
  2. 醤油 (japanska Wikipedia) (retrieved 2026-08-15)

Compiled by Basim Ali Yoshiguchi. .