Kiku tsuyu (broth) is "Dashi-shoyu (soy sauce with broth)" .
Dashi shoyu is so popular in Japan, since you can easily enjoy authentic taste, such as Soba, Udon or source for Tempra. When using, please add some water to dilute it to your taste, as this is concentrated type.
It's base is Kikubishio, another popular soy sauce of Yamaroku shoyu, made from black soy beans, which are known as the diamonds of the fields and grown in Tamba City (丹波市) in Hyogo prefecture.
Also, kelp is from Hokkaido, bonito is from Makurazaki, brown sugar and mirin is from Tanegashima island, Kagoshima; high quality ingredients.