9 Dots

Did you know

• Chinese nicknames include 麻子臉, "pockmarked face".¹
• One of the thirteen orphans: a 1 or 9 of each suit and every honor make kokushi musou.
• As the dora indicator it wraps around: face up on the dead wall it makes the 1 of dots dora.

At the table

• A terminal fits in only one sequence, so it is the hardest number tile to use and often the first to go.
• It is suji to the 6: once an opponent has discarded , a two-sided wait on the 9 would leave them furiten, which makes it a safer discard against them.
• It is dora when is the dora indicator. Turned up as the indicator itself, it makes dora.

Yaku it can help

• Chanta a terminal or honor in every set
• Junchan a terminal in every set
• Honroutou terminals and honors only
• Chinroutou terminals only
• Kokushi Musou one of the thirteen orphans
• Chinitsu one suit only
• Chuuren Poutou the nine gates, all in one suit

Where the dots come from

Each dot is a coin: a round copper cash with a square hole, the everyday money of imperial China, straight from the coin suit of the money cards mahjong grew out of. A minority theory has them as the end of a gun barrel instead.²¹

Its Chinese names are 筒子 tǒngzi, "barrels", and 餅子 bǐngzi, "cakes". Japanese players first read 筒子 as tonzu; the pinzu they say now survives from the cakes. English speakers call the suit dots, circles or coins.²³

Sources

1. 麻雀牌, Wikipedia (Chinese) Chinese
2. Mahjong tiles, Wikipedia
3. 麻雀牌, Wikipedia (Japanese) Japanese