In Kagawa Prefecture, which is known for Sanuki udon ("Sanuki" is the old name of the prefecture), many households have their own "dashi-joyu" (soup stock seeped into soy sauce), which is used as an udon sauce.
また讃岐うどんで知られる香川県ではつゆの作成のために出汁の成分をそのまま醤油に抽出させただし醤油というものが、よく家庭に置かれている。