Japanese horror stories are different from stories of other countries. Many of Japanese horror stories are based on onryo meaning "vengeful spirit" or "vengeful ghost".

A person who is killed by other person's selfish reason may become onryo after death. He may revenge. He may not be able to forgive the opponent. The opponent is living with fear, will have some troubles or accidents, or will be died. Anyway the opponent cannot be out of sufferings physically and mentally.

http://en.wikipedia.org/wiki/Onryo

Onryo is like a ghost. A person with strong grudge makes his own soul go to his target of grudge, and give sufferings for revenge. That is living onryu.

A dead person become an existence of only soul and revenge. That is dead onryo.

Onryo have strong grudge and must revenge. People are afraid of onryo. But people understand the grudge is natural and sympathize with onryo.

Most of grudge is about love affair or politics.

One of the most famous stories of onryo is "Yotsuya Kaidan".

Oiwa was a beautiful woman. Her husband had an affair and killed Oiwa by poison. Oiwa's face was broken by poison and she died with grudge. Her husband's related persons died one after another. He is the last. He was filled with fear. Finally he was killed by Oiwa's onryo.

http://en.wikipedia.org/wiki/Yotsuya_Kaidan

It is nonfiction. About 1100 years ago, Sugawara no Michizane was an excellent minister. He fell into trap and lost his position. He died with grudge. After his death many natural disasters occurred. People thought that his onryo causes such disasters. He was worshiped as a god "Tenjin". Nowadays he is a god of knowledge. Many students worship him.

Even Tenno, Japanese emperor, had become onryo. In 1156, the war occurred between current Tenno and previous Tenno, Sutoku. Sutoku army was defeated. Sutoku was exiled and died with grudge. After his death, Tenno's family died one after another and many natural disasters occurred. People thought they are the curse of onryo. Before death Sutoku said "I will be devil. I will set Tenno under samurai!"

In 1192, samurai became the king of Japan. Tenno lost his power. Government of samurai continued until 1868.

http://en.wikipedia.org/wiki/Emperor_Sutoku

In Japan winners cannot flee from grudge of loser. It is important how win. If a winner give sufferings to a loser, the winner should pray for the loser. Japanese winners are afraid of the losers. Winners are not true winners. Can you understand?

We are afraid of onryo. We are afraid of grudge. We should not give anybody sufferings. Then we have had the culture of not making onryo. Winners treat losers with respect. I think it is the law of cause and effect, too.