Three labels, three different signals
- Counterintuitive choice: a non-answer candidate has more immediate effective tiles.
- Wait quality: both candidates reach tenpai, but the answer leaves a materially wider live wait.
- Shape preservation: the answer gives up immediate acceptance to retain at least two clean, independent blocks.
Why one-step counting loses information
Immediate acceptance asks which tiles improve the hand on the next draw. It does not describe the wait created afterward. Two candidates can each show eight tiles while one repeatedly reaches two-sided waits and the other reaches inside waits. Counts can also be inflated when two blocks need the same tile.
Tingpai Lab therefore asks a narrower but deeper question: which discard is more likely to complete by self-draw within the evaluation horizon? Tenpai hands use two draws and one-shanten hands use three. An improvement is reevaluated from its new shanten state.
A repeatable comparison
- Preserve the best shanten.
- List effective tiles and subtract visible copies.
- Inspect the wait produced after each draw.
- Check whether blocks are independent or overlap.
- Compare limited-horizon self-draw probability.
The common mistake
Giving up acceptance is not valuable merely because the remaining hand looks neat. Shape matters only when it improves the path to completion. Late in a hand, immediate tenpai and current live tiles may deserve more weight.
Limits
This comparison excludes scoring, defensive value, opponent speed, and yaku. A narrower path can still be the better table decision when it preserves safety or meaningful value.