Researchers have studied mahjong as a mentally demanding social activity for older adults. Findings are promising but not conclusive. Here is what is known, and what is not.
Seven pairs is a special hand of seven different pairs. It is a standard yaku in riichi and a scoring hand in MCR and many Chinese styles, but not allowed everywhere.
Moving from one style to another trips up even experienced players. Here are the habits that cause the most mistakes — calling chows in American play, forgetting yaku in riichi, keeping flowers in the wrong game.
Three-player Japanese mahjong, sanma, removes the two-to-eight of characters and turns the North wind into a bonus tile. It is faster, swingier and very popular in Japan.
Riichi scoring combines han, from yaku and dora, and fu, from the hand's composition and wait. Together they give a base value that is multiplied for dealer and non-dealer wins, up to the mangan limit and beyond.
Some wins earn extra faan because of how they happen: robbing a kong, winning on a kong replacement tile, winning on the last tile, or the legendary heavenly hand dealt complete.
A dead hand can no longer win. In American play it happens when you have the wrong number of tiles, your exposures match no hand on the card, or you call Mah Jongg in error. Here is how it works.
In Hong Kong mahjong is part of the city's fabric: licensed mahjong schools with neon signs, family games at festivals, and a fast, gambling-flavoured Cantonese style that has spread worldwide.
After 1949 mahjong was discouraged as a form of gambling and bourgeois idleness, and during the Cultural Revolution sets were destroyed. Since the 1980s it has returned as a mass pastime and an official sport.
The moment of winning has its own words and rules. Learn how to declare a win on a discard or a self-draw, how hands are checked, and what happens if a declaration is wrong.
The tile that should show a single bamboo stick almost always shows a bird instead. The sparrow, peacock or phoenix on the one-bamboo is one of mahjong's best-loved mysteries.
