the hardest physical and mental thing i have ever done if by far my black belt testing. It was no 2 hour taekwando test with a 1 hour written exam.
No, mine was 48 hours non stop, no sleep, little water and a few oranges to keep me going. Hours upon hours of doing forms as hard as possible, endless drills,, annything that would tax your mind and your body (break falls, pushups while reciting the codes of isshinryu, throwing techniques as hard as you can, every time, fighting till you had tunnel vision. After 36 hours of 60 other black belts working you out till you broke, then you fight, full bore for an hour to 2. In that time frame i dislocated my already injured shoulder twice, got 2 ribs cracked, a concussion, broken toes and a messed up knuckle or 2. I passed out from sheer exhaustion after being promoted. The only thing that kept me going were my brothers, the other guys i was testing with. After a year of working out till you could barely stand, you become something different.
By far the hardest thing i have ever done, and possibly will do