1. In Japan, we have 2 types of soy source.
◆Koikuchi (dark) Soy Source
“Koikuchi” is the one you use for sushi. Even though it is called as “Koikuchi”, which means dark or stronger in Japanese, this type of soy source is less salty than another one. “Koikuchi” is used for cooking, but also as a sort of source you drizzle to the food, like when eating sushi.
◆Usukuchi (light) Soy Source
You would have little occasion to try “Usukuchi” in your country. “Usukuchi” means light or weak, but as I mentioned, it’s more salty than “Koikuchi”. “Usukuchi” is used when cooking . This is not put at dining table, but kept in a kitchen.
２. Soy Source with sugar doesn’t exist in Japan.
“Sauce Soja Sucrée” was invented for French people
If you are French, you should have tasted this sweeten soy source. Many French people love to drizzle this sweeten soy source on the rice and even on sushi. But this “Sauce Soja Sucrée (Sweeten Soy Source)” is invented only for you guys!!
３. Usukuchi : Kansai area / Koikuchi : Kantō area
Different food culture
In Japan, Kansai area (Western part of Japan) and Kantō area (Eastern part of Japan) have different food culture. Traditionally, in Kansai, people cook with Usukuchi more than people in Kantō do. On the other hand, people cook with Koikuchi in Kantō. This photo is a good example. Both of these two box are the same instant ramen. However, the soup powders accompanied are different.
The left one is sold in Kansai area and the right one if in Kantō area. Now you can see obviously the color of soup is different. “Usukuchi” for Kansai and “Koikuchi” for Kantō.
Kansai area : “Usukuchi”
Kantō area : “Koikuchi”
４. Kikkoman vs Higashimaru
In Japan, we have 2 biggest mark when it comes to soy source. They are “kikkoman” and “Higashimaru”.
Then…which to take??
If you come to Japanese super, you will find a giant Soy Source section which you have never seen in your country. Then, you would be at a loss, “Which one to take??”
Traditionally, it is said that when it comes to “Usukuchi”, buy the one from Higashimaru. It may be because Higashimaru is originally from Hyōgo, in Kansai area. So the soy source of Higashimaru is admitted soy source in the hometown of “Usukuchi”.