Four men, gathered around a dimly lit table full of tiles while smoking, betting money and drinking, is the typical image of mahjong.
But a new "healthy" variety--playing the game without these vices--has been increasing in popularity among the nation's elderly.
Experts say players utilize cognitive functions and build dexterity through the movement of their fingers, which could help prevent aging.
Each morning from Monday to Friday, men and women aged 60 or older gather to play mahjong in a room at a building in Shinagawa Ward, Tokyo.
"Ron!" one shouts, indicating the player is about to win the game. Another chuckles and says, "I could almost make a winning hand."
It is a fun event with players enjoying themselves irrespective of whether they win or lose.
These players are members of "Ikiiki Kenko Majan Hiroba" (a plaza for lively, healthy mahjong), which was started by the ward government in 2002 to provide elderly people with a new lease on life.
The healthy version of mahjong is attracting an increasing number of women who are newcomers to the game, betraying the ward office's expectation.
In fiscal 2011, about three-quarters of the participants in the Shinagawa event were women.
At a beginner's course that began in April last year, all 24 people who took part in a session on one day this year were women who had never played mahjong before.
The women have spent the past year under the tutelage of instructors who have taught them mahjong's rules and strategies.
"When I compete a winning hand, I feel great," said Sachiko Kaneda, 67, who attends the course.
"I can't wait to play each week. My husband likes the game and I now talk to him more [because of mahjong]," Kaneda said.
She has also made friends with mahjong players enrolled in the course and sometimes has lunch with them.
The goal in mahjong is to collect 14 tiles and group them into four sets consisting of three tiles each and one matched pair.
A set can either be a "pon," three identical tiles, or a "chow," three consecutive numbers of the same suit.
Kaneda starts by making a set and then tries to complete a winning hand with 14 tiles.
She said her first priority is enjoying the game, winning or losing comes second.
The Japan Kenko-Mahjong Association suggested the creation of "healthy" mahjong and co-organizes the Shinagawa ward government's project.
While mahjong is often thought of as a late-night game that involves drinking and smoking, the association has been promoting a healthy version of the game to elderly people since 1988.
In 2007, this version was officially included in the "Nenrinpic," a national sports and cultural festival for senior citizens.
Nenrinpic is a combination of the word "Olympic" and "nenrin," which refers to the rings of a tree in Japanese.
About 100,000 people participated in healthy mahjong classes last year, which were held nationwide at about 100 locations.
Some of the classes are co-organized by the association and local governments.
Association secretariat official Makoto Togamae gave an explanation of the rules:
-- Technical terms such as "pon," "chow" and "ron," should be said clearly during the game.
-- When you discard a tile, don't slam it on the table.
-- After the game finishes, don't analyze it.
-- While you are not playing, don't watch another game over a player's shoulder.
-- Don't play the game for too long a time.
-- Try to perform exercises such as bending and stretching during breaks from the game.
"I heard from many senior participants, who used to stay at home, that they go out more often and pay greater attention to their appearance and makeup after attending the healthy mahjong class," Togamae said.
A professor specializing in neurology, Kikunori Shinohara, at Tokyo University of Science, Suwa, in Nagano Prefecture, said mahjong could assist elderly people.
Shinohara said cognitive functions could be stimulated through a range of activities, such as figuring out how to finish the game, reading the facial expressions of other players and making conversation.
"Playing in a group of four is a good influence," Shinohara said.
Shinohara recommends the elderly play other games such as board games and jigsaw puzzles, while chatting with family and friends.