In the Kanto region, a basic sauce called "Kaeshi" is inevitably used for soup broth, made by heating up dark-colored soy sauce while applying Mirin (sweet cooking rice wine) and sugar (some restaurants use 'Nama-Kaeshi' [literally, raw Kaeshi], unheated basic sauce).
関東では濃口醤油を加熱しながらみりんや砂糖を加えてつくるかえしと呼ばれる下地を用いる（加熱しない「生がえし」を用いる場合もある）。