The Urban Legend:
Onryō 怨霊 or Revengeful Ghosts are wraiths born from a violent death or suicide. These Spirits are known to haunt places or objects related to their pain, suffering or obsession. The Onryo are feared because they are known to harm, curse, kill or otherwise bring calamity to the living. In some cases the wraith's grudge is so strong that they directly haunt the person or people responsible. However, in such a case, the spirit usually leaves them alive to insure their life is only suffering.
One of the most famous cases of an Onryo haunting was found in Japan. Emperor Kanmu accused his brother of plotting to take his throne. This accusation was believed to be unfounded, but his brother was still exiled and starved to death in the wilderness. A short time later the Emperor's close collaborates all started dying one by one. He knew vengence was coming for him. To escape his brother's wrath Kanmu moved and changed what city was the capital twice, but he couldn't get away. Unnatural weather and dark omens followed him. Desperate to appease the wraith, Kanmu held a Buddhist ritual in which his brother was given the title of an emperor after his death. Fortunately for him it was successful, which is rarely the case.
A more modern example of an Onryo haunting is the triangle house, found in the town of Ama, which is part of the Aichi prefecture. This house is said to curse anyone who enters with misfortune, illness, madness or death. The couple who had the house built committed suicide inside. Since, the place has accumulated many stories of ghost sitings and tragity with anyone who has been involved with the house. So be careful where you enter. That abandoned house, the dilapidated park or the overgrown cemetery just may have earned its terrifying legend and it could be your last stop.