Soy sauce (dark or Koikuchi)
Soy sauce is the most essencial condiment of Japanese cuisine. It is made from paste of boiled soybean, roastd wheat grain and brine. Longer fermentation period makes more aromatic soy sauce. Koikuchi (※dark) soy sauce is the must-have. It is an all purpose soy sauce that you can use for any of Japanese cooking.
※It is defferent from Chinese dark soy sauce.
It contains 15% of salt.
Kikkoman is my favorite brand.
Soy sauce (light or Usukuchi )
Usukuchi (light) soy sauce can be used when you don’t want to make your dish in a dark color, especially if using a beautiful color ingredients like white meat fish or grean peas.
Usukuchi contains more salt than Koikuchi. Make sure to use smaller amount than Koikuchi. Ushukuchi is used especially in Kansai (west of Japan) region for its delicacy.
It contains 18% salt.
Higashimaru is my favorite brand.