Count capacity before counting blocks
A standard 13-tile game needs four melds and one head; a 16-tile Taiwanese hand needs five melds and one head. Each completed meld reduces the number of candidate blocks the hand can use. Blocks beyond that capacity cannot all survive to completion, even if each has attractive draws on its own.
Four concepts narrow the diagnosis
Block overload says blocks and pairs exceed the remaining capacity and the answer returns the hand to a usable count.
Weak-block trimming is more specific: while overloaded, the answer breaks an independent edge or inside block. It supersedes the broader overload label.
Pair collision describes adjacent pairs such as 55m66m. They compete for the head and can obstruct sequence use. The label applies when the answer removes that collision.
Overlapping acceptance describes independent blocks that need the same tile, such as 23m and 56m both accepting 4m. Adding their headline counts double-counts a resource and overstates independence.
Cleanup sequence
- Subtract completed melds and count the remaining meld candidates plus one head.
- List blocks and pairs without assigning one tile to two roles at once.
- Mark edge, inside, and nearly dead blocks.
- Mark adjacent pairs and shared effective tiles.
- Compare shanten, live acceptance, and limited-horizon winning probability after each possible cut.
Limits
Overlap does not automatically mean “break it.” Long runs and compound shapes may share tiles while creating broad improvements. Treat overlap as harmful only when the discard restores usable capacity and the candidate comparison supports the cut.