Red 5 Bamboo

Did you know

• Each red five in a winning hand adds 1 han, like a dora. See aka dora.
• Parlors have gone much further: red 3s in Kyushu, and gold, silver, pink, rainbow and even blue fives, the blue ones worth a han less. Some red tiles carry a raised dot for colour-blind players.¹²
• Red and green don't mix: like the plain 5 of bamboo, it can't go into ryuuiisou.

At the table

• It fits in three sequences, the most any tile can.
• It is suji to the 2 and 8: once an opponent has discarded and , a two-sided wait on the 5 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

• Aka Dora each red five adds 1 han
• Tanyao simples only
• Chinitsu one suit only
• Chuuren Poutou the nine gates, all in one suit

Where the bamboo come from

The sticks aren't bamboo. They are strings of coins: 索 means rope, and copper cash were threaded through their square holes in strings of a hundred. The bumps along each stick are the coins on the string.³²⁴

Joseph Park Babcock, whose 1920 Rules of Mah-Jongg are the earliest mahjong rules known in America, took the bumps for bamboo knots, and the English name stuck.³⁵

Sources

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