According to Robert Twigger in Angry White Pyjamas, because you washing them would dissipate the ki (mystic energy), so by the time you reached that level belts were already naturally black
Why are black belts black?
August 18, 2008 at 11:55 pm (Aikido, Japan FAQs and SAQs, Japanese books/ Books about Japan, Japanese martial arts, Japanese religion and superstition, Judo, Karate, Ki (mystic energy))
Brent said,
August 19, 2008 at 12:36 pm
My guess: Because you can dye a white belt black, but not vice versa.
I had a friend that did judo, and every time he advanced he dyed his belt to the new colour. The order being convenient for that because the colours get progressively darker (in Canada the order is white, yellow, orange, green, blue, brown, black).
fightinchick said,
November 30, 2008 at 2:03 am
Traditionally, it was said that after all the work you put into going from a white to black belt, your belt would be so dirty that it would just become black. Now, things have changed. We have degrees or dans, and they must be put on by hand/machine. Some dojos give you a black belt when you’ve reached that level in your training and others unfortunately just want your money. Either way, you’re not supposed to wash it because of the “ki” and it stands for all you’ve worked for.
Sierraa. said,
December 9, 2008 at 8:08 pm
Erm. Brentykins, you sir, are wrong.
BLEACHH!!!