Interesting things about China video

There were 2 things I found to be very interesting about the discovery channel China video. The first was the martial arts training seeing the martial artists standing behind the pales of water and striking the water with their hands. I am wondering why this would help them in a fight maby because it would build up tollerance to pain in their hands/ arms.
the other thing that intrigued me was seeing the farmers constructed the rice fields by having them set in layers. the only explanations that i can think of is that either this is because the area has many hills and this would be the easyest way to do it or because the design is better for irrigation among the rice or possibly a combination of the two.