https://en.wikipedia.org/wiki/Tanomoshiko

Tanomoshiko (also spelt Tanomoshi-ko or Tanomosiko) (Japanese: 頼母子講) ("reliable group")[1] is a variety of rotating savings and credit association (ROSCA) found in Japan. Historically they played a major role in economic life in Japan and among the Japanese diaspora, and still survive on an informal basis in some parts of the country.

Seems like they were also important in so-called buraku communities.
#頼母子講 #ROSCA