With permission of the author, Tina Koshimoto, NARMA is glad to share the third in the series of Tina's Tactics.

“May 28th 2018, Mr. Takeo Kojima, a Mahjong Legend also known as Mr. Mahjong, passed away at the age of 82. I was deeply saddened when I learned of this, as I studied his books greatly and thought of him as my Sensei.

When the news of his passing hit, Kojima-sensei’s fans from all over the world were moved by his loss and my feed was covered with videos of Sensei playing mahjong. Perhaps you saw one of the famous videos of him winning 九蓮宝燈 (Nine Gates) in an official league/tournament game. This is just one of the many Yakumans that Kojima-sensei won in his lifetime, as his playing style was set on winning the biggest hands. He thought of 1000 or 2000 point hands to be “boring”, and his book also discusses the mindset of always aiming for a Mangan or higher.

I wanted to take some time to talk about Kojima sensei and his playing style, not only to pay respect and to honour him, but also because I wanted to highlight the importance of establishing your own playing style.

There are different play styles and each mahjong player will have his or her own way based on personalities and preference. Are you the Occult type that believes in your luck and reads the Nagare at the table? Are you the more modern, Digital type that focus on tile efficiency and winning a faster hand? If you, like Kojima-sensei, know and have established your personal style already, great! However, most players including me are somewhere in between and are still trying to figure out what works best.

Where do we start?

So, we all want to be better, right? Sure, but where do we start? Some people eventually get an idea after playing enough games, but for someone like me who prefers to plan things out, I need at least a general idea on where I need improvement.

To do this, I found my player statistics on Tenhou to be useful. I believe most of the readers already play on or at least know of Tenhou so I won’t go into the details to introduce it, but if you are not familiar with it, I recommend you to read through Ch.1 of Riichi Book 1, written by Mr. Daina Chiba.

As described in Ch. 2 of the same book and on http://arcturus.su/wiki/Tenhou.net_ranking, Tenhou analyzes your playing and will provide certain data. I believe players can benefit from looking at these numbers, since it gives you a general idea about the strengths and weaknesses of your playing style, which can then give guidance on points that need improvement.

Working on Defense

I find 放銃率 (Houjuu ritsu) – Deal in rate % – to be especially important because if you are dealing in too much, then you can still place lower even if you were winning often.

Houjuu ritsu – 放銃率 – Deal in rate %
Low (defensive) 10~11%
Average 12~13%
High (aggressive) 14~15%

If your Houjuu ritsu is too high, you may want to take time to learn more about defense strategies and study Ori techniques. Defense is something I am also personally working on too, which is why my previous two articles focused so much on defense techniques.

Working on Tile Efficiency

For some, mahjong is all about winning and getting that adrenaline rush. 和了率 (Houra ritsu) – Hand win rate % is a good indicator on how often you are winning.

Houra ritsu – 和了率 – Hand win rate %
Low (defensive) 20~21%
Average 22~23%
High (aggressive) 24~25%

If your 和了率 is low, you should study more about tile efficiency and going into Tempai faster. If you come under this category, you should also look at your common tendencies in aiming for Tempai.

Fuuro ritsu – 副露率 – Call rate %
Low (Menzen-type) 28%
Average 35~36%
High (speed-type) 40%

Riichi ritsu – 立直率 – Riichi rate %
Low (speed-type) 14%
Average 16~18%
High (Menzen-type) 20%

Generally a higher Fuuro ritsu will lead to higher Houra ritsu because you can get to Tempai faster, but could also lead to higher Houjuu ritsu because you have less tiles in your hand and this can leave you defenseless against others’ Tempai.

On the other hand, a player with higher Riichi ritsu is taking time to build his/her hand. This could mean slower Tempai and thus lower Houra ritsu, but the winning hand are generally worth more. Menzen style allows more options when folding too, as the player can choose the discard from the entire 14 tiles.

Working on Hand Building

Lastly, some players who have a high Houra rate may still struggle placing higher against the other opponents because their winning hands are too cheap, or “boring” as Kojima-sensei would say. In other words, winning 4 or 5 hands of 1000 points may give you higher Houra rate, but cannot win against a single winning Mangan. 平均得点 or 平均和了点 (Average score) would be an indicator on how high you are scoring with your winning hands, but this includes uma and oka on Tenhou so it is not exactly raw data. Nonetheless, it can give you a general idea.

If you are facing this issue, take some time to study the different Yaku and work on tile efficiency with number of Hans in mind. If your Fuuro ritsu is on the higher end, consider thinking twice before calling Pon or Chi so that you can keep your hand Menzen, which gives you the option to Riichi and potentially more points.

Interesting Patterns

Page 40 of Chiba’s book looks at hand-performance statistics across the Tenhou players and shares how the deal-in rate steadily decreases as players move up the ranking. He emphasizes the importance of defensive skills, and I would like to second this.

If you look at the Tenhou rank players’ data shared on a blog by mahjong writer Makoto Fukuchi (http://fukuchi.cocolog-nifty.com/blog/2015/03/post-a7cf.html), the average 和了率 (Houra ritsu, discussed below) is 20% and 放銃率 is 10.6%.

The same pattern applies offline too. Mondo TV provides the similar data on the Pros at http://www.mondotv.jp/…/mpl-of…/ranking/winning_tile_average, and when we look at the average rates of the 5 players with the most number of games, the average 和了率 is 20% and 放銃率 is 10.3%. Amazingly similar!

When we look at Kojima-sensei’s data in the Mondo TV database, his 和了率 is 18.22% and 放銃率 is 8.43%. Interestingly, even though he was known for his “flashy” play style, the numbers show how he was a defensive player. Again, this shows how defensive skills are crucial in mahjong, and aiming for larger hands is not an excuse to carelessly push all the time.

May his legacy live on and inspire many others to follow his path.

Resources

https://www22.atwiki.jp/vipdetenho/pages/306.html
http://majandofu.com/mahjong-winning-rate
http://blog.livedoor.jp/kazucchi4465/archives/25810696.html”