This sushi refers to warm Bara-zushi (scattered sushi), also called Nuku-zushi (warm sushi) or Mushi-zushi (steamed sushi), which was handed down in the Chugoku and Shikoku regions in the west of Kansai.
ぬくずし、又は蒸しずしと呼ばれる関西以西、中国、四国地方に伝わる温かいバラ寿司の事。