The origin of a word 'kan' is uncertain because of many theories, but there is a theory that one roll of Norimaki (or sushi in the rolled style such as Sasamaki-zushi (sushi wrapped in a bamboo grass leaf), Bo-zushi (rod-shaped sushi topped with large slice of fish, and so on) was counted as 'one kan' (in this case, 'kan' means roll).
「かん」の語源は諸説あり定かでないが、海苔巻き（もしくは笹巻き寿司や棒寿司などの巻いた形式の寿司）1つを「1巻」と数えたことからという説。