The comparison & result
This study compared ready hands that always declared riichi when allowed with ready hands that never declared. It tested two fixed habits, rather than selecting a declaration for each hand.
The archived report recorded win shares of 55% and 45%, and averages of roughly 481 and 175 points per hand. The simulation version did not enforce furiten, and the report did not publish uncertainty intervals. Those limitations prevent treating these figures as validated advice for a real Riichi table.
At your table
Use the result to question a blanket habit. A particular hand can still favor a different decision because of its value, wait, available tiles or opponents.
Check your table’s scoring rules before applying the finding. Read the Japanese Riichi reference.
How it was tested
Tested in the Hé Fēn Lab: 100,000 hands played by the same engine that scores your games — permanent declarers against permanent quiet hands, seats swapped so the deal is fair.
The players were software policies, not human participants. This report describes the published experiment; it does not establish the best move for every possible hand or opponent.
Results without a published uncertainty interval should be read as point estimates. Similar results do not prove two choices are equivalent.
Read the Lab’s method and limitationsPublished by Hé Fēn Mahjong. Ask about this finding or suggest a correction.