Many of us have read RB1, played with the hand efficiency trainer, and learned a thing or two from Feng's intermediate mahjong slide deck. If you are trying to progress in jokyuu or tokujou I suggest taking a look at these as a form of practice and study if you haven't already.
Riichi Book 1 by Daina Chiba: https://ooyamaneko.net/download/mahjong/riichi/Daina_Chiba_-_Riichi_Book_1_en.pdf
Mahjong Efficiency Trainer by Euophrys: https://euophrys.itch.io/mahjong-efficiency-trainer
Intermediate Mahjong Slides by Feng: https://mahjong.guide/wp-content/uploads/2019/10/Riichi-Strategies-Workshop-2018-by-Feng.pdf
What I'm going to be sharing here is something I learned in the last month or so that was eye opening for me. Perhaps it will help you as well. Folks over at the Competitive Riichi Hub Discord were discussing pair+ryanmen shapes (ie 556) where the most blindly efficient thing to do is hold the whole shape until it fills up by drawing 4, 5, or 7. Keeping this shape also allows acceptance of whatever tiles make up a pair elsewhere in your hand when applying to a perfect iishanten (one away from tenpai that always gives you two sided wait).
Depending on what turn it is, this can be a problem especially when you're lacking value. When you get tenpai late in the game and you've been hugging this shape to death, you are going to have to throw a middle tile to the wolves, some of which could even be in riichi themselves. The concepts I will be sharing are taken directly from 現代麻雀最新セオリー (Gendai Mahjong Saishin Theory) published in 2017. The book is largely stats driven and is focused on improving free and online mahjong play.
It's turn 8. We've drawn this north and it's time to figure out what to cut. I strongly believe many intermediate players are just going to immediately dump the north in order to keep acceptance of 2s and 4m along with the ryanmen-ryanmen wait. However, the book suggests this is incorrect and it is time to drop the 4m from the hand and keep a safe tile. In a way, it makes sense: if you draw 2s or 4m, are you going to riichi nomi? This may be an okay maneuver in aka nashi (especially in this situation with a half dead guest wind dora), but with none of the reds visible to you in ari, or in a situation with a more usable and dangerous dora, you might be defenseless against an oikake or someone opening to make a tanyao.
For the statistics, let's look at a chart that immediately follows the answer to this WWYD that analyzes the difference between the options here:
The solid pink line is "safe tile remaining ryanmen-ryanmen iishanten". The black line is the "kanzen iishanten" (a perfect one away where you have to throw a 4, 5 or 6). The light pink line with the empty boxes shows the same wait, but the tile that has to come out to take tenpai is a 2, 3, 7, or 8. The x-axis here shows which turn it is, and the y-axis displays the expected value (EV).
Notice that around turn 6, the EV of the shape when the tile is a center tile is thrown drops below that of just keeping the safe tile around for an eventual attempt to win. At around turn 8, the outer tiles are similarly problematic. The book goes on to show a similar scenario:
Here, the correct answer is to tsumogiri. Since it is before the threshold where outer tiles become more of a liability than a benefit (the image is at turn 6 and turn 8 is the cutoff) we should keep the perfect iishanten.
As for how this has helped me recently, keeping this idea in mind when I am working with a cheap hand has allowed me to fight back in games when another player is pushing. I've rid myself of the dangerous tiles ahead of time, and if I draw into tenpai before something comes where I need to betaori, I can either dama to stop the hand or safely oikake riichi depending on the situation. The dama pinfu nomi has already netted me a handful of riichi sticks, especially when the wait is on the genbutsu of the player in riichi.
To paraphrase a comment in the original discussion, we seek to maximize our win rate, not just our tenpai rate. Dealing in with an unsafe middle tile in the second row to push is no more a "muh tenpai" than trying to call for keiten and dealing in when there are less than a dozen tiles left, in my opinion.
Riichi Book 1 by Daina Chiba: https://ooyamaneko.net/download/mahjong/riichi/Daina_Chiba_-_Riichi_Book_1_en.pdf
Mahjong Efficiency Trainer by Euophrys: https://euophrys.itch.io/mahjong-efficiency-trainer
Intermediate Mahjong Slides by Feng: https://mahjong.guide/wp-content/uploads/2019/10/Riichi-Strategies-Workshop-2018-by-Feng.pdf
What I'm going to be sharing here is something I learned in the last month or so that was eye opening for me. Perhaps it will help you as well. Folks over at the Competitive Riichi Hub Discord were discussing pair+ryanmen shapes (ie 556) where the most blindly efficient thing to do is hold the whole shape until it fills up by drawing 4, 5, or 7. Keeping this shape also allows acceptance of whatever tiles make up a pair elsewhere in your hand when applying to a perfect iishanten (one away from tenpai that always gives you two sided wait).
Depending on what turn it is, this can be a problem especially when you're lacking value. When you get tenpai late in the game and you've been hugging this shape to death, you are going to have to throw a middle tile to the wolves, some of which could even be in riichi themselves. The concepts I will be sharing are taken directly from 現代麻雀最新セオリー (Gendai Mahjong Saishin Theory) published in 2017. The book is largely stats driven and is focused on improving free and online mahjong play.
It's turn 8. We've drawn this north and it's time to figure out what to cut. I strongly believe many intermediate players are just going to immediately dump the north in order to keep acceptance of 2s and 4m along with the ryanmen-ryanmen wait. However, the book suggests this is incorrect and it is time to drop the 4m from the hand and keep a safe tile. In a way, it makes sense: if you draw 2s or 4m, are you going to riichi nomi? This may be an okay maneuver in aka nashi (especially in this situation with a half dead guest wind dora), but with none of the reds visible to you in ari, or in a situation with a more usable and dangerous dora, you might be defenseless against an oikake or someone opening to make a tanyao.
For the statistics, let's look at a chart that immediately follows the answer to this WWYD that analyzes the difference between the options here:
The solid pink line is "safe tile remaining ryanmen-ryanmen iishanten". The black line is the "kanzen iishanten" (a perfect one away where you have to throw a 4, 5 or 6). The light pink line with the empty boxes shows the same wait, but the tile that has to come out to take tenpai is a 2, 3, 7, or 8. The x-axis here shows which turn it is, and the y-axis displays the expected value (EV).
Notice that around turn 6, the EV of the shape when the tile is a center tile is thrown drops below that of just keeping the safe tile around for an eventual attempt to win. At around turn 8, the outer tiles are similarly problematic. The book goes on to show a similar scenario:
Here, the correct answer is to tsumogiri. Since it is before the threshold where outer tiles become more of a liability than a benefit (the image is at turn 6 and turn 8 is the cutoff) we should keep the perfect iishanten.
As for how this has helped me recently, keeping this idea in mind when I am working with a cheap hand has allowed me to fight back in games when another player is pushing. I've rid myself of the dangerous tiles ahead of time, and if I draw into tenpai before something comes where I need to betaori, I can either dama to stop the hand or safely oikake riichi depending on the situation. The dama pinfu nomi has already netted me a handful of riichi sticks, especially when the wait is on the genbutsu of the player in riichi.
To paraphrase a comment in the original discussion, we seek to maximize our win rate, not just our tenpai rate. Dealing in with an unsafe middle tile in the second row to push is no more a "muh tenpai" than trying to call for keiten and dealing in when there are less than a dozen tiles left, in my opinion.
Let's not be this guy, and sakigiri when it's appropriate! Obviously when looking at the chart it's noticeable that the lines track fairly close together, and when dora are introduced, or other yaku like tanyao, it increases the value of holding the larger avenues to tenpai... however it does nothing to reduce the danger of the middle tile if you have to throw it too late. This book covers a lot - it's over 200 pages! I will continue sharing tidbits that help as I find them. Please let me know, through comment, discord, or other means if you found this helpful!
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