The superb Tom Guald enters the dojo (although he's unlucky on the 50% risk when drawing Japanese martial jimjams: getting the keikogi wrap the wrong way round)
Untested converse hypothesis: In martial arts that technically and philosophically deny the punching of people in the kisser (looking at you, aikido), surplus hair grows out on the other side → more males sprout ponytails than evolution might otherwise allow.
If you practice an unarmed percussive martial art that requires you to get punched in the chops, do your research and consider growing a beard. https://t.co/VLPmqedq1D
That's the Ig Nobel [Peace] Price lecture from 2021: "Impact Protection Potential of Mammalian Hair: Testing the Pugilism Hypothesis for the Evolution of Human Facial Hair"
1969 documentary on Japanese sword-making (includes some questionable commentary, including unverifiable "silent prayers"... but it's clearly a well-meant eulogy to the bother Japanese swordsmiths were willing to go to) https://t.co/ZHiCdEDS1r