is 1 . Every tile is 2 through 8. A 1, a 9, or any honor removes it.
The name players use is tanyao (断么九). This site's glossary also lists it as All Simples.
Open or closed
The han stays when you call. , , and an are allowed, and the yaku is still 1 han. The EMA 2016 rules put that on the list. The edition before them scored tanyao only on a . Mahjong Soul allows the open hand too. On Tenhou it's a lobby setting, on in the main ranked lobbies and off in one that few people play. The yaku list states the same rule.
This waits on 
, , or . The pair of 8s is already there. The 34567 is a : read it as 34 and 567 and it takes 2s or 5s, or as 345 and 67 and it takes 5s or 8s. Each winning tile completes a two-sided shape.
Every tile is 2 through 8, so the hand is tanyao. It is also pinfu: closed, four sequences, a plain pair, and a . A on any of the three tiles is 2 han 30 fu.
The glossary entry is the short form: no terminals and no honors.
What a simple open hand pays
An open hand with no fu past the base 20 counts as 30. At 1 han 30 fu, a ron collects 1,000. The dealer collects 1,500. Those payments have no and no sticks.
A closed tanyao won by tsumo also has menzen tsumo, so count that han too.
What sits with it
can sit in the same closed hand when all four sets are sequences and the wait is two-sided, as in the hand above. A tanyao pair is never , so the pair never blocks it. An honor removes tanyao, and honitsu requires one, so a hand is never tanyao. A one-suit hand with no honors is chinitsu. Tanyao can sit in that hand when every tile is still 2 through 8.
Price a tanyao hand
The score calculator turns 1 han 30 fu, the open hand with no extra fu, into 1,000 or 1,500. Add honba when the table has them.
Open the score calculator