Saishikomi soy sauce

Main ingredient: 

Saishikomi (doubled-brewed) soy sauce is produced from equal amounts of soybeans and wheat, but used double amounts than one in regular soy sauce, as is is made with regular soy sauce (Koikuchi) instead of water and salt. 

Mainly used for:

As it is much darker and more strongly flavored, and contains more "umami", and natural sweetness, it is getting popular and used as sauce for raw fish or every ingredients especially eating by raw. 
Also, it takes long time to produce Saishikomi soy sauce, only 1% or less of Japanese soy sauce is "Saishikomi" soy sauce.