Dora variations
Akadora
Akadora is the usage of red dora. Most commonly, they are the 5's to each numbered suit. Some house rules apply red dora to any of the other tiles as well.
- One – Each numbered suit had one dora each.
- All – Every red dora tile in the mahjong set is used. A set may come with four red 5's: 1 souzu, 1 manzu, and 2 pinzu.
- Nashi – None are used.
- Option – Players have the option to select the use of akadora or not.
- Extra – More than one tile type is indicated as the red dora.
Kandora
After declaring a kantsu, another dora indicator is flipped in the dead wall. All four players can benefit from this.
- Sokunori – After declaring any type of kantsu, flip the next dora indicator immediately.
- Late – Timing on the kandora is dependent.
- After declaring ankan (concealed kantsu), flip the next dora indicator immediately.
- After declaring a minkan (open kantsu per call on a discard or per extension of a minkou), flip the next dora indicator only after discarding. If rinshan kaihou occurs, then the new kandora is not revealed.
- If chankan occurs, no kandora is revealed.
- Nashi – Kandora is not used.
- Start – One kandora is revealed at the beginning of each hand.
Kanuradora
Winning riichi declarers may flip the tile underneath each kan dora indicator and treat that as another dora indicator.
- Ari – The kanuradora is used.
- Nashi – The kanuradora is not used.
Uradora
Winning riichi declarers may flip the tile underneath the first dora indicator and treat that as another dora indicator.
- Ari – Flip the ura dora indicator.
- Nashi – Not used. Riichi declarers will know in advance how much their hand is worth.