The sport of Sumo wrestling has picked up quite a few traditions during its long history. One of these traditions is that the tate-gyoji, the two most senior referees, wear a knife. This knife symbolizes the referee's willingness to commit seppuku, i.e. ritually disembowel themselves, if the ringside judges reverse their decision.
In modern practice, this has been replaced by the referee tendering his resignation which is generally summarily rejected. This has happened a number of times. I am curious, however, is there a record of a referee having committed ritual suicide?