To explain why I thought this was interesting: from what I read, a Tanomoshiko is (mostly "was") an informal mechanism for loans. If one person was in financial hardship, a group of several people would each contribute a small sum of money, thus curing the hardship. Instead of ordinary repayment, the group would now repeat the same act in a few weeks, but choosing another person in the group (perhaps at random) to receive the money. This would repeat until everyone had been payed.<p>There were and are taboos around loans in many societies (our own included). This seems like it's probably part of a broader family of methods for working around those taboos.<p>I came across this only from a side remark in Yukichi Fukuzawa's autobiography. I don't know of a good source (the wikipedia article is admittedly not great).