there were the married couple of the god of the man and woman called Izanaginomikoto and Izanaminomikoto. there was the son named Susanoonomikoto with the daughter named Amaterasuoomikami, in them. Amaterasuoomikami is the goddess of a gentle older sister and Susanoonomikoto is the god of a fine younger brother.
Susanoonomikoto was a violent god. He was about to cause to have difficulty Amaterasuoomikami. And he finally has got defeated in the distance.
when Susanoonomikoto walks the country of Izumo alone this way, and be beaten a daughter was crying with father and mother.
He heard the reason of crying. They said him," The monster serpent called Yamatanoorochi that has eight head comes to eat our daughter soon.
he had them made the fence around the house right now.
after a while, suddenly became dark the monster serpent turned up. It is a very fearful figure and the red eye was glistening with glaring for eight heads.
and he started to drink alcohol vigorously, when he found jars. then after a while he intoxicated and slept.
Susanoonomikoto plucked up his courage and cut to the monster serpent with the sword. The monster serpent that noticed and flied to Mikoto.
However, he cuts the monster serpent attacking him in succession and threw down. And the monster serpent has been exterminated finally.
He gets married to the daughter who he saved named Kushinadahime and lived happily.
when Susanoonomikoto was traveling through a town,man named Sominshourai,a very poor man,offered him a place to stay while others wealthy people refused. Susanoonomikoto gave a ring of sprout for wife and daughter to wear it to prevent from plague. Later Susanoonomikoto wiped entire village with epidemic.
so pople place chimaki for charm and protection.
http://yamagamin.iza.ne.jp/images/user/20060706/3358.jpgyasaka jinja shirine
http://web.kyoto-inet.or.jp/org/yasaka/english/index.html