yubitsume

Yubitsume (指詰め; 'finger shortening') is a Japanese ritual to atone for offenses to another, a way to be punished or to show sincere apology and remorse to another, by means of amputating portions of one's own little finger primarily performed by the yakuza. These days, however, it is not as widely practiced anymore and replaced with simply giving the offended party loads of cash.

To perform yubitsume, one lays down a small clean cloth and lays the hand onto the cloth facing down. Using an extremely sharp knife, or tantou, the person cuts off the portion of their left little finger above the top knuckle on the finger or the tip of the finger. They then wrap the severed portion in the cloth and submit the "package" very graciously to their superior – or to whomever this gesture of atonement is made.

If more offenses are committed, then the person moves on to the next joint of the finger to perform yubitsume. More infractions could mean removing portions of the right little finger when no more joints of the left finger remain. In some cases, a person expelled from a yakuza gang might be required to perform the yubitsume ritual.