Dora variations

The use of dora may be subject to variation.

Akadora

Use some red fives in place of normal fives as extra dora.

Ari – Use three red fives, one per suit.
Nashi – Don't use any red fives.
Option – Tenhou.net offers both rules in different games. Akadora ari may be played with kuitan ari.
Additional - Along with the red fives, other tiles among the numbered suits or even the honor tiles may be indicated as dora.

After declaring a kantsu, another dora indicator is flipped in the dead wall. All four players can benefit from this.

Ari – Flip a new kan dora indicator after declaring a kantsu, but I don't know the exact timing rules.
Sokun. – Sokunori. After declaring any type of kantsu, flip the next dora indicator immediately.
Late – 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 declaring tsumo, declaring another kan, or discarding. The new dora indicator is in effect for any type of win.
Nashi – Don't flip any dora indicators upon declaring kantsu.

Winning riichi declarers may flip the tile underneath each kan dora indicator and treat that as another dora indicator.

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.