By Hiroyuki Muramoto

TOKYO (Reuters Life!) - In Japan, Halloween is an opportunity to release your inner child. Or your inner girly vampire-nurse. Or your inner pirate-themed Santa Claus.

Thousands of revellers in costumes that would make any witch feel underdressed took to the streets of Kawasaki on the outskirts of Tokyo in one of Asia's biggest Halloween parades, adding a Japanese twist to the ghostly festival.

Thumping techno beats accompanied the 100,000-strong street party on Sunday, and the panoply of elaborate outfits showed Japan's love for fantasy worlds and fancy dress.

"At first, people would question us about why we were celebrating Halloween," said Tomoko Tsuchiya, manager at Citta Entertainment, which organised the event.

"But now its more like: 'Alright, its Halloween. Sounds fun'. These events are recognised by a lot of people now in Japan."

Halloween is one of Japan's newest festivals, although a similar local ritual exists -- the summer festival of Obon, when the dead are believed to briefly return to visit the living.

As with most Western festivals in Japan, the focus is on having fun rather than on getting it right and being authentic.

Women dressed as French maids and school girls, and a Santa Claus wearing a pirate's eye-patch at the Kawasaki parade were a nod to the Japanese past-time of "cos-play", or dressing up as your favourite cartoon character or animated movie star.

Shops and bars in Tokyo have been gearing up for Halloween since September, displaying jack-o-lanterns, bats and inflatable witches and ghosts. Some cafes sell special Halloween treats such as pumpkin-shaped sweets on top of chocolate cakes.

Flower shops also pile up huge pumpkins, often adding hand-written Japanese explanations of Halloween and trick-or-treating.

And like children at Halloween parties everywhere, the little witches and wizards at the Kawasaki street parade seemed to be torn between feeling excited and a bit scared by all the weird monsters on show.

"I think it's great that all these people are in so many different costumes," said 11-year-old Miori Mori as she watched the parade.

"But it's actually a bit frightening," Kaeda Abe, another 11-year-old, replied.