2 Dots

Did you know

• Its best-known Chinese nickname is 眼鏡, "glasses". In Taiwan it is also the snowman.¹
• The glasses came later. On 19th-century tiles the two coins touch, like a figure 8; by the 20th century they had pulled apart into round spectacles.²
• Ryan comes from Chinese 兩 liǎng, the word Chinese uses when counting two of something, rather than 二 èr, the bare number.³

At the table

• It fits in two sequences, one fewer than the middle tiles.
• It is suji to the 5: once an opponent has discarded , a two-sided wait on the 2 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

• Tanyao simples only
• 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.⁴¹

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.⁴⁵

Sources

1. 麻雀牌, Wikipedia (Chinese) Chinese
2. 二 一九世紀の中国麻雀牌（プロト・マージャン）, p. 3: 19th-century tile designs, Japan Playing Card Museum (日本かるた文化館) Japanese
3. 麻雀の「イー、リャン、サン、スー」の「リャン」と漢字の「両」の話, Toyo Seiki blog Japanese
4. Mahjong tiles, Wikipedia
5. 麻雀牌, Wikipedia (Japanese) Japanese