Iishanten: Difference between revisions

'''Floating tile''' '''iishanten''' describes the case where there are two complete groups and a pair, with two incomplete groups waiting to be completed. One tile (the East tile in the example hand) does not contribute to any group, and so is said to be floating.

'''Complete iishanten''' is an improvement on floating iishanten when all tiles in the hand contribute to the iishanten. In the example hand, the 445s group now has three tiles working together. This hand is also an example of '''perfect iishanten'''. Perfect iishanten is a special type of complete iishanten that guarantees a ryanmen wait. If we draw 369s2p, we can discard 4s for a multisided wait. If we draw 4s, we discard 5s.

=== Atamanai ===

'''Headless iishanten''' is a hand where we have three complete groups, no pair, and one or two incomplete groups. An ideal headless hand will have two ryanmen groups waiting to be completed. If either of these groups completes, then the hand becomes tenpai with a tanki wait. If we pair one of the four tiles, then we can discard the other tile in its incomplete group to get a ryanmen wait on the other incomplete group.

'''Sticky iishanten''' is identified by three complete groups, one pair, and two floating tiles (37s in the example above). This type of iishanten tends to have the largest range of acceptable tiles to bring it to tenpai (any souzu tile in the example). However, the downside is that many of these draws may leave a narrow, non-ryanmen wait.