Hanako is one of the most famous ghosts in Japanese folklore. In short, Hanako is a female ghost that haunts school toilets. It doesn't matter that there are bazillions of schools in Japan there's apparently one Hanako assigned to each school, spooking the unfortunate girl who happens to be at school late at night and needing to pee. Whether Hanako is a good or evil ghost depends on the variation of the story you hear.
Does Hanako really exist? Some people actually really think so. Some school teachers, working at school late at night, have attributed unexplained phenomena they experience, such as hearing the water faucet in the bathroom running when there's no one else around, to Hanako. While it's hard to comprehend for a foreigner, having grown up reading and hearing about Hanako, this belief is hard to shake off for the Japanese.
A TV station once featured Hanako in one of its TV shows featuring the spooky, (supposedly) real ghost videos. In one episode, two TV personalities (along with video camera crew) ventured into an abandoned, closed-down school building to verify the existence or non-existence of Hanako for everyone in front of the TV screen.
Apparently, there are a number of variations on how to summon Hanako, but in this episode, one of the TV personalities had to lie in wait at a bathroom stall, all by herself, with a video camera. The stall door was closed. Other video cameras were positioned at various parts of the bathroom. The other TV personality (who was a male) was stationed at a nearby room with the other video camera crew - they could (safely) watch the situation in the bathroom with the multiple TV screens set up in the room. Communication between the people in the safe zone and the one sacrificial lamb was possible via microphones and headsets.
Time ticked by and nothing happened. The poor lady in the bathroom stall was getting more spooked by the moment... After some time, there was a sound of knocking on the door of her stall.
No one else could be seen in the bathroom, and no one was visible outside the stall door. Needless to say, the lady looked like she was going to freak out.
After what seemed like endless minutes, the door began to slowly open by itself. According to some rule, if you encounter such a situation, you must not close the door... or something bad would happen to you. The lady knew this rule, and the other guys kept on reminding her of it, so tempting as it was, she didn't close the door.
But as the door opened wider, the lady couldn't take it anymore: She kicked open the door in a way reminiscent of a police officer kicking open a door, with pistol ready and shouting Don't move!. Then she dashed out of the bathroom, screaming as she went along. Interestingly, on her way out, she managed to lose a slipper, but stopped for a moment to retrieve it before continuing her escape.
Conclusion: The existence of Hanako could not be verified because of the lady's unexpected actions. It is entirely possible that the TV producers did not seriously believe that Hanako did exist, and they simply used her to entertain the audience. While the situation looked real and all from beginning to end, the fact that TV personalities were involved, the fact that this was a variety show shown on prime time, and most important of all, the fact that the lady actually stopped to retrieve her slipper even though she was scared to death all strongly support this view. However, the stall door did mysteriously open by itself, and no one could be seen on the camera screen. The sound of the door being knocked on seemed real as well. Perhaps some trick was involved, and it was all a setup by the producers? Or perhaps...?