Learn about the Godlike status of the Emperor
The Japanese people were actually taught that their Emperor was of divine origin. So, for them in battle, a supernatural protection would be in effect. Many believed that bullets would simply bounce off them in battle because they were fighting for their God Emperor.
Such beliefs in the Godlike status of the Emperor have existed in Japan for well over a thousand years.
Just like here in Oz.
Taking life one deity time.
And do bullets bounce off me? No, they hurt like shit but they haven't killed me yet.