Years ago when I first came to Asia, I trained at a place that used real tatami. It was a pretty hard surface, and when it's new it's very hard.
My teacher emphasized a lot of breakfalls. I trained for one hour in the morning and three hours at night. I can't even imagine how many breakfalls I took in a day, but I'm sure it was in the hundreds.
Anyway, I began training in November. One night in spring, after returning home exhausted, I washed my gi and went to bed. Just as I was falling asleep, a mosquito landed on my cheek. I slapped it reflexively and almost knocked myself out.
I realized at that moment that all of those breakfalls had truned my hands into weapons.