Yubitsume

In modern times, it is primarily performed by the yakuza, a collection of Japanese criminal organizations.

[1] The ritual is thought to have originated with the bakuto, itinerant gamblers who were predecessors of the modern yakuza.

[2] If a person was unable to pay off a gambling debt, yubitsume was sometimes considered an alternative form of repayment.

The reason for this is that in Japanese swordsmanship (kendo and iaido), the sword cannot be held tightly, and the little finger's grip is the tightest on the hilt.

In some cases, a person expelled from a yakuza gang might be required to perform the yubitsume ritual.