Hundreds of Pokemon Go fans gathered in Yokohama, southwest of Tokyo, on Sunday to join an annual Pikachu parade as the global phenomenon soars in popularity.

Some 50 life-size Pikachu characters, the most famous from the Pokemon game, marched along the city's waterfront street as visitors took mobile phone pictures and videos of them in scorching sunshine.

Some participants said they attended the event to search for rare characters of Pokemon -- a word short for "pocket monster" -- for the megahit smartphone app, which was launched last month globally.

"I came here all the way to Yokohama, hoping to find different kinds of Pokemon characters," said Teruko Fujisawa, a 45-year-old woman working at a trading house.

The event had no direct link with the app, organisers said.

Since its global launch, Pokemon Go has sparked a worldwide frenzy among users who have taken to the streets with their smartphones.

The free app uses satellite locations, graphics and camera capabilities to overlay cartoon monsters on real-world settings, challenging players to capture and train the creatures for battles.

Pokemon has been popular in Japan since first being launched as software in 1996 for Nintendo's iconic Game Boy console.

It expanded into other media, most notably a wildly popular TV animation show and its popularity has never waned.