American Mahjong Hand Structure Checker
This checker helps you review the structure of a possible American mahjong hand without copying any annual-card line. Enter the group sizes shown by the spacing on your current card, mark singles or pairs that must remain natural, and compare the total with the fourteen positions required for a complete hand.
Build the Printed Group Pattern
Choose the size of each separated group exactly as it appears on the current card. This checks structure only; it does not confirm that the tile identities, colors, suits, year digits, or exposure status match an official hand.
Start With the Card Spacing
Add each visibly separated group, then run the check.
What This Checker Can and Cannot Confirm
The tool can verify arithmetic and flag common structural issues. It cannot determine whether a specific annual-card hand is legal, because legality also depends on the exact printed line, color relationships, suit assignments, exposure designation, and current official rules.
Use the Result Correctly
- Copy group boundaries from the current card, not from memory.
- Count printed positions rather than physical tiles hidden behind jokers.
- Mark singles and pairs as natural-only.
- Review quint and sextet requirements carefully.
- Confirm whether the printed hand is concealed or exposed.
- Recheck the actual line before declaring mahjong.