Multi hanchan format
In a multi hanchan format, the same four people play multiple hanchan. After each hanchan, the final scores (after oka and uma) are summed, and whoever has the highest cumulative score wins the series. Ni hanchan, or literally "two hanchan", is a format that lasts for two hanchan.
This format is mainly used in tournaments and leagues, where a single hanchan is not enough to determine standings. Playing multiple hanchan helps reduce the impact of luck. The exact number of hanchan used depends on the organizer and the amount of time possible to settle a result.
Strategy
- Due to oka and uma, your placement at the end of each individual hanchan still matters. Rising up a rank in all last can result in a big point gain.
- Early on in a series, playing for expected points is more valuable. For example, going for kokushi with 10 unique tiles has a good expected value, but it has a low winrate, and 32000 points is overkill for a single hanchan. In a multi-hanchan, the 32000 points isn't overkill, so kokushi at 10 tiles becomes a stronger play.
- Late in the series, playing for end-of-series score becomes very important (akin to playing for placement at the end of a single hanchan). For a league or tournament, players will have a rough estimate of what score is required to make top cut. Players that are behind may need a yakuman or double yakuman to catch up.