Mahjong Other: Pro associations in Japan

This article describe the characteristics of each Mahjong pro associations in Japan.

Hi all, thank you for checking this website. I got a request to write on Mahjong pro associations in Japan. Actually I don’t know much on the exact difference, but I’ve seen interesting video of Genki Hirasawa, Pro of AJMJA, famous writer of Mahjong strategy books, and Youtuber. This is a summary and translation of that video on Youtube.

To write this article, I got approval from him. Thank you, Hirasawa san ! You can watch his video from the link below. Well, let’s get started !

【Mリーグ】Mリーガーたちが所属する「プロ団体」の違いやルールを解説

First is on JPML from 2:51. This is the largest association, to which as many as 16 M leaguer belong.

Feature of their rules in internal league is No Ippatsu, No Uradora, No red 5 Dora.

Position point is +8k for 1st, +4k for 2nd, -4k for 3rd and -8k for 4th without Oka: bonus point for 1st, very small compared to the other format.

So players of JPML tend to 1. go for high scoring hand and 2. push when they have large chance to complete high scoring hand. So delicate judgement of push or fold is not so important in this rule.

Next is on Saikoui-sen from 5:55. This association has 9 M leaguers.

Feature of their rules in internal league is ｗith Ippatsu, and Uradora, no red 5 Dora.

Position point is +30k for 1st, +10k for 2nd, -10k for 3rd and -30k for 4th without Oka, relatively large. So push/fold judgement and technique to control the opponents is important. This rule seem to be moderate among these associations, which allows various types of players to compete. For example, style of Sonoda and Murakami is totally different, but both are the top players in this association.

Next is on NPM from 10:11. This association has 2 M leaguers.

Feature of their rules in internal league is with Ippatsu, and Uradora, No red 5 Dora.

Position point is +30k for 1st, +10k for 2nd, -10k for 3rd and -30k for 4th with Oka (20k), largest among these associations. So it is important to maximize the probability of getting 1st, and players tends to go for slow but high scoring hand from bad Haipai: opening hand.

Next is on Mahjong Rengou from 12:01. This association has 1 M leaguer.

Feature of their rules in internal league is no Ippatsu, no Uradora, no red 5 Dora.

Position point is +12k for 1st, +4k for 2nd, -4k for 3rd and -12k for 4th without Oka, similar to JPML. They don’t have no-Tenpai Bappu which player pays at exhaustive draw.

Players who are good at simply winning hand tend to win in this rule.

Last part is on RMU from 14:24. This association has 1 M leaguer. (Btw, this picture doesn’t looks like Oi, himself.)

Feature of their rules in internal league is with Ippatsu, and Uradora, No red 5 Dora.

Position point is +15k for 1st, +5k for 2nd, -5k for 3rd and -15k for 4th without Oka, Smallest position point among the associations whose rule is with Ippatsu and Uradora.

In this rule, round EV optimal decision tends to be game EV optimal.

Good player will adjust their style to the rules, but you will see some players at each association can’t fit into M league’s format well and stick to their style.

Lastly let me introduce Hirasawa’s Youtube channel. His contents is addressed to Tenhou 3-5 dan, If you speak Japanese. https://www.youtube.com/channel/UCwhNnYUXoyQGe0snQnYF2BQ

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