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Editor’s Notes

Greetings from the Pocket Concierge Editorial Team!
Soy sauce, Japan’s favorite condiment, has today been widely accepted into the world’s kitchens. The country’s economic and cultural prevalence has certainly helped this; however, none but sushi can claim to have done more in spreading the word, given its explosive growth in world-wide popularity. Nowadays, it is common sense to have sushi alongside soy sauce; but not many spend the time to think ‘why?’, even in the presence of Japan’s many soy sauces. In this article, we seek to answer such queries; ‘Why do we eat sushi with soy sauce?’; ‘Why are there multiple varieties of soy sauce?’. Continue reading below to find the answers.


1. The Origins of Sushi; Preserving Seafood

2. Soy Sauce; Its Varieties and Different Uses

3. Summary

The Origins of Sushi; Preserving Seafood

Image: Irifune Sushi|Pocket Concierge
Sushi, like many forms of cuisines, was originally born as a method of preserving raw foods. In the case of sushi, its origin, ‘nare-zushi’ was a seafood preservation format utilizing salt and rice. A form of pickling, nare-zushi used the compound’s lactic-fermentation capabilities to preserve raw seafood; however, unlike current day sushi, only the seafood pickled was eaten, and elsewhere the rice used discarded. This pickled seafood dish had a mild sourness accompanied by a saltiness akin to modern-day fish sauce, and while considered an ancient delicacy, was highly time consuming to create. To compensate, it became common in later eras to instead of fermenting add vinegar for acidic pang; thus, the current day combination of seafood and vinegared sushi rice was born.
On a similar note, the Japanese dish ‘sashimi’, slices of raw fish commonly eaten with soy sauce and other condiments, is also said to have been derived from ‘namasu’, a format of eating fresh meats and seafoods; like early versions of sushi, ‘namasu’ too was commonly eaten with vinegars and other seasonings.
It was not until the 17-19th century Edo period that soy sauce and its variants grew popular; ‘Irizake’, an early soy sauce-like condiment made using sake and pickled plum, grew to be an indispensable member of the Japanese kitchen and preferred partner to sashimi. However, while this condiment was especially good with light-tasting seafoods, it lacked the strength to partner with richer-tasting fish, and also lacked preservative qualities. Thus, when soy sauce, previously limited to small-scale regional production, became mainstream, ‘irizake’ gradually faded out.
Mid-Edo period Japan was peaceful and prospering; this led to a massive population burst, and an increase in commercial activity. Such movement of people was what brought modern-day soy sauce, a condiment only available in small quantity do to unstable production, to a broader audience. The influx of producers led to newer methods and scale, making this new, longer-lasting, stronger tasting condiment widely available. These qualities, which overcame the shortcomings of irizake, gradually led to soy sauce’s overtaking of its predecessor as the darling of Edo-Japan’s kitchens, and cemented its position as the primary partner of sushi.

Soy Sauce; Its Varieties and Different Uses

‘Soy sauce’ is not one item at a grocery store; rather, it is a genre, with multiple products and varieties that can confuse the unknowing shopper. But while soy sauce can come in all shapes and sizes, it can also be categorized into 5 main archetypes; koi-kuchi (dark), usu-kuchi (light), tamari (rich), sai-shikomi (twice-brewed), and shiro (white). Knowing the characteristics and main uses of each may help you in your future shopping trips, at least in buying what label to buy for your day’s dinner menu. Below are the 5 soy sauce archetypes and their qualities, as listed by the Japan Agricultural Standard.

‘Koi-Kuchi’ Dark Soy Sauce

Originally from the Kanto region of and around Tokyo, ‘koi-kuchi’ is the standard dark-colored soy sauce; well-balanced in flavor, aroma, and color, it has since spread to a broad following throughout the country, and is commonly quoted to be over 80% of domestic soy sauces production. Essentially the population’s go-to option regarding soy sauce, ‘koi-kuchi’ is all-mighty, perfect both as on-table condiment and ingredient, and popularly used in almost any culinary format from grill to stew.

‘Usu-Kuchi’ Light Soy Sauce

Those having been to the Kansai region of Japan, the western states encompassing popular destinations such as Kyoto, Osaka, and Hiroshima, may have noticed; the broth common in the region dishes, whether udon noodles, stews, or soups, tends to be much more lightly colored compared to their Kanto counterparts. This is due to the different soy sauce that is the anchor of the area’s cuisine, a more generally lighter soy sauce that is the ‘usu-kuchi’; thanks to its non-overbearing qualities, ‘usu-kuchi’ fits perfectly with cuisines like that of Kyoto, where it is of utmost importance to maximize the flavor of ingredients. However, one thing worth noting is that despite its lighter color and aroma, ‘usu-kuchi’ actually has a higher sodium content compared to ‘koi-kuchi’. By utilizing high salinity to shorten the fermentation and maturation processes, ‘usu-kuchi’ production realizes a short brewing schedule alongside its uniquely useful qualities.

‘Tamari’ Rich Soy Sauce

The darling and traditional soy sauce of the Chubu region of Japan, centered on the industrial hub of Nagoya, ‘tamari’’s ingredients set it aside from the more common ‘koi-kuchi’ and ‘usu-kuchi’ sauces. While the latter two use a 50-50 combination of soybeans and wheat as a brewing base, ‘tamari’ uses solely soybeans, and is well known to be highly flavorful and umami-rich. While apt for use with sashimi, the reddish color and savory-rich qualities of ‘tamari’ are especially notable when used to season menus that involve a slight burning of the condiment, such as the summer delicacy ‘unagi’ eel, ‘senbei’ rice crackers, and grilled ‘mochi’ rice cakes.

‘Sai-Shikomi’ Twice Brewed Soy Sauce

Hailing from the northern province of Yamaguchi, ‘sai-shikomi’ is, as per its name, brewed twice; the final brewing process uses a previous batch of ‘koi-kuchi’ as substitute for more common flavoring ingredients, resulting in a thick, dark-colored, strongly-flavored condiment well suited for partaking with both sushi and sashimi.

‘Shiro’ White Soy Sauce

The opposite of ‘tamari’, ‘shiro’, or quite literally ‘white’ soy-sauce uses almost completely wheat as its base; hence, it is even lighter in color and aroma than the similar ‘usu-kuchi’. Also commonly used in the Kansai region, this light, slightly sweet soy sauce is oft-used as a subtle undertone, or highlight, of ingredient-appreciative dishes.


The history and varieties of soy sauce can be confusing to many, and the popularity of the condiment as sushi’s best friend may be perplexing to still more. In the paragraphs above, we have attempted to explain this in a simple and engaging manner, and hope to have been able to lend a hand to those desiring to know more about the realities of soy sauce and it bond with sushi.
Of course, ‘understanding’ is not the same as ‘knowing’, much less ‘tasting’ or ‘experiencing’. And although of course it is possible to do a tasting of various soy sauces and perhaps different seafoods alone, with ingredients bought at your neighborhood grocer, to fully appreciate the marriage of the oft-underappreciated sushi-soy sauce relationship, we would highly recommend the restaurants below, or any one of our highly-acclaimed sushi restaurant partners. For a truly enjoyable gourmet sushi experience, do try our Pocket Concierge service out!

Sushi Tatsunari

A firm Ginza establishment already, despite its relatively new entrance into the fiercely competitive world; Tatsunari serves the freshest out of Tsukiji in a masterful chef’s course, alongside sake from the chef’s native Aomori. His visionary creations of Tuna make for a expansive can’t miss new-world of sushi.

Irifune Sushi

In the rustic backwaters of Tokyo’s residential south, enjoy the mouthwatering finest of bluefin tuna in myriad style; different cuts, fresh or seared, with a variety of savory condiments, like the signature garlic soy sauce. Join the line of gourmands making pilgrimage to this sanctuary of sushi.


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