For newcomers or current residents in Tokyo, where people are known to sometimes come off as cold and distant, attempting to chat up a complete stranger on the street or in a bar can make even the biggest social butterfly feel shy.

"I've been in Japan for two and a half years and I couldn't find the right peers. I came to a point where I was super-introverted," says Joji Kurosawa, who moved to Tokyo from the Philippines in 2011. "But I know in myself that I'm a very social person."

Kurosawa found a solution when he discovered Tokyo Pub Crawl, a mass bar-hopping event held three to five times a month in Roppongi and attended by Japanese and foreign drinkers alike. They're recognizable on the streets of Roppongi on a Saturday night, a long stream of revelers led by a staff member holding a large sign and yelling out instructions — and followed by curious looks.