Background: The informant is my father. The informant is well aware of the culture surrounding martial arts such as Tae Kwon Do and Jiu Jitsu as his children have been practicing martial arts for almost a decade, and he also practiced martial arts himself when he was younger.
Context: I spoke to the informant while eating dinner with my family and I addressed the topic of folklore to my father.
Main Piece: My father remembers hearing while at my martial arts academy that whenever a Jiu Jitsu practitioner washes their belt, they are believed to have lost some of their skills and techniques. The Jiu Jitsu practitioner is free to wash their ‘Gi’ (traditional Jiu Jitsu uniform), whenever they please, as not washing one’s uniform after training will leave it rancid. However, the belt is not to be washed as when one washes their belt, they are essentially washing away all of the techniques and skills they have learned.
Interpretation: When my father told me about this Jiu Jitsu superstition, it rang a bell in my head because I had heard this multiple times on the mat myself. I remember one day a black-belt admitted to cleaning their belt and many people were poking fun at him and saying that he had just lost exactly 75% of his techniques. Of course, this is more of a running joke from my experience then an actual superstition that people still believe, however it is still relevant. In my personal interpretation, when you wash your belt, you are essentially getting rid of all the sweat and dirt that symbolize your efforts to learn and grow as a Jiu Jitsu practitioner.