Question: What are the Charleston moves, and do you have to complete all of the them except for the last optional across pass?

Answer: The first three moves of the Charleston are compulsory. The second Charleston is optional and can be continued unless someone chooses to stop it with exception, if East, who has 14 tiles after the deal, has Mah Jongg, the Charleston is waived.

Charleston moves:

First Charleston:

1. First Right
2. First Across
3. First Left

Second Charleston:

1. Second Left
2. Must Across
3. Last Right
4. Optional Across

Source: Mah Jongg Made Easy 2024, Page 12 & 13