Anyone living in Tokyo has passed dozens of 'janso' -- Japanese Mahjong parlors. Few, however, dare to actually go inside, perhaps anticipating a dark, smoky den that will erupt in a slow-motion gangster assassination at any moment.

But those that think that have probably been watching too many Wong Kar-Wai movies, as this image could not be farther from the truth. Mahjong parlors are welcoming places and a great space for social activity. The only thing is, if you want to join the janso club, you'll have to learn how to play mahjong.

Here are nine good reasons to take the plunge into miles and miles of tiles.

It's popular

With over 8 million players playing in over 10,000 parlors across the country (and countless playing at home), mahjong is the most popular table game in Japan. "Mahjong is a great game and Japanese people love it," says Takunori Kajimoto, noted mahjong author and manager of the Mahjong Museum in Chiba.

It's easy to learn

Mahjong looks complicated at first, but if it was really that hard, millions of people wouldn't be playing it. Learning the basics takes a bit of time, but there are plenty of internet resources to help you out. For example, www.reachmahjong.com, run by American mahjong professionals Jenn Barr and Garthe Nelson, is a great place to start.

Networking

'Ningen kankei,' interpersonal relations, is a crucially important part of Japanese society. Since nearly all senior male company workers in Japan have played mahjong at one point in their life, learning the game can be your key to getting some face time with the big shots in the top ranks.

It's safe

Gambling in Japan has long been associated with organized crime, but gangs pulled out of the mahjong world years ago. Most big parlors nowadays know that keeping customers loyal means keeping them safe, so expect well-lit interiors and staff watching out for any funny business.

More and more parlors are also offering student and sub-student level rates, so if you're nervous about your game you won't be losing more than ¥1,500 an hour. There are even parlors that cater to beginners. One that has been known to be very foreigner-friendly is Shibuton (Dogenzaka 2-10-12 3F, Shibuya-ku, tel 03 5456 8158, www.shibuton.jp).

Competition

Whoever says that Japanese people are 'not competitive' has never played mahjong. Try sitting down at a table with three of them who are trying to take your money.

Mahjong keeps you healthy

Recently, people in the mahjong world have been promoting 'healthy mahjong,' a special way of playing aimed at keeping the minds of the elderly ticking. You may have your doubts, but momentum has snowballed, and the movement has gathered government funding for its national tournaments. Now during retirement you can claim that your addiction to the game is a neurological treatment.

Wacky manga

Want to see Hitler and the Pope duke it out at the mahjong table? Only mahjong aficionados are able to understand the bi-weekly manga serial "Kindai-Mahjong," which has some of the most entertaining -- and ridiculous -- comics in the world. Pick one up at your local convenience store.

Mahjong Museum

Yes, a mahjong museum exists in Japan, and it's the only mahjong museum in the world. The museum is located an easy day-trip from Tokyo near Kazusa-ichinomiya on the Sotobo line. They even have a picture of the emperor playing mahjong. E-mail the manager Takunori Kajimoto at kaji.mahjong@gmail.com in advance for a personal tour. (Nakabara 1-2, Misaki-machi, Izumi-shi, Chiba Prefecture, tel. 03 3264 1576, 10am-5pm, closed Mondays)

It's fun!

The main reason mahjong is so popular is because it's a great game. Japanese Mahjong games only end because someone has to catch the train or meet his girlfriend. No one ever leaves because they're sick of playing.