In addition, there is a theory that says that the name comes from 'mamamushi,' which is a special cooking method in the Kansai region (to be precise, in the areas to the west of Lake Hamana and Lake Suwa), in which the eel is broiled without first steaming it, placed on top of the rice, and then buried under additional rice in order to steam it.
他に、関西での調理法（正確には浜名湖・諏訪湖以西。）の特色である、蒸さずに蒲焼にして、飯の上に乗せた上に更に飯を乗せて蒸らす「飯蒸し」（ままむし）から来たという説がある。