Modern rules

Descends into

• Modern riichi / yonma — red fives, 1970
• Sanma — 3-player riichi
• WMPA / WMF — Korean, riichi-based

Cross-comparison

corroborated — two or more independent sources agree on the facts that define this variant

• [1] in 1967 Amano published the 'modern rules' (gendai ruuru), introducing rounding fu up to the nearest ten, bazoro, oka and ura-dora, all still used today
• [2] states that the 1967 Modern rules introduced 2 HAN bazoro, oka and uradora. The '2 han' is the detail that reconciles this with the 1957 Tokyo rules, which already had a variable dice-driven zoroba: what 1967 introduced was the fixed two-han form still baked into modern scoring tables, not the idea itself

Reading it

Two independent sources agree that the 1967 rules introduced bazoro, oka and ura dora, exactly as the chart says. There is an apparent conflict with the 1957 Tokyo rules, which already carry a zoroba, and it resolves cleanly: riichi.wiki specifies that 1967 introduced TWO HAN bazoro, the fixed form still built into modern scoring tables, where 1957 had a variable bonus rolled on the dice that did not count toward the minimum. The chart's attribution is correct once bazoro is read as the fixed form.

Sources

1. Yuria (Hassouhatsu Club). "A Brief History of Japanese Mahjong." Krakow Chombo Club, 2 Aug 2026. canonical checked 2026-09-18

   Arushiiaru rules and scoring; Amano Daizou; the Houchi Shinbun serial of 11 Nov - 5 Dec 1952; the 1957 Tokyo rules and 1967 modern rules; bazoro; the Federation's 2016 acceptance of riichi.

   https://chombo.club/en/blog/2026/08/02/a-brief-history-of-japanese-mahjong/

   Also cited on: Japanese classical / arushiiaru, Houchi rules, Tokyo rules, Modern riichi / yonma, WMPA / WMF · bibliography #10

2. Japanese Mahjong Wiki. "Daizo Amano." riichi.wiki. cross-check checked 2026-09-19

   Biography and complete ruleset list for 天野大三 (1904-1982): the 1952 Hochi rules and the police incident, and the seven rulesets he authored between 1952 and 1978. Read through the Wayback Machine.

   https://riichi.wiki/Daizo_Amano

   Also cited on: Houchi rules, Modern riichi / yonma · bibliography #72