Although red adzuki beans are better for eating than black-eyed peas, the former could be regarded as inauspicious since it might easily crack in body (or peel), which would remind one of seppuku (suicide by disembowelment), so that black-eyed peas may be used instead of adzuki beans, especially in the Kanto region.
食味的には小豆の方が上であるが小豆は胴割れ（皮が破れること）しやすく切腹を連想させて縁起が悪いとされ、特に関東地方でささげを用いることが多い。