Testing a rewrite for atozuke:
Atozuke 「後付け」 is the state of a hand that is severely dependent on calls to complete the hand. The cases where a hand is caught in an atozuke position are:
- when a hand is waiting on a tile that will provide it its winning yaku, such as
Agari: or [no riichi call]
- when a hand has opened up and is not dependent on the first call to score the yaku, such as
-
Agari: or
Cases that are not atozuke are when the hand contains a fully concealed yaku (yakuhai, sanshoku, ikkitsuukan), such as:
-
Agari: 
or or
... or when the first call confirms the yaku, such as:
Agari: or [sanshoku doukou confirmed]
... or when the hand aims for an obvious hand condition, such as:
Agari: or or [hon'itsu confirmed/obvious]
However, calling for a group and then aiming to complete something with it falls under atozuke conditions, such as:
Example
This hand uses a shanpon tenpai for two tiles. One may produce a yaku, while the other does not.
- Agari: or
In the event of haitei, houtei, or even rinshan, the issue of atozuke here would become moot, as yaku may apply to either winning tile.
Risk of furiten
- Draw:
Particularly, open yakuless hands run the risk of furiten. That is especially true if the above example draws a 9-pin during the course of the hand, when additional tile draws remain in the wall. In this case, a player cannot declare a win and must discard any tile in the hand. Upon doing so, the player become furiten and must work around it, by changing its hand composion with the remain tile draws or other player discards.