Defending strategy: suji

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Mauro
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Defending strategy: suji

Post by Mauro » Thu Sep 10, 2015 9:47 pm

Reading Osamuko's blog, I found about various kinds of suji and aida yon ken: http://osamuko.com/umaikeiki-defense-gu ... -and-suji/ Then I read Just Another Japanese Mahjong Blog (http://justanotherjapanesemahjongblog.blogspot.it/), in which it is said:

http://justanotherjapanesemahjongblog.b ... nding.html
Part of the outdated theories have also been proven to be wrong. (Such as ura-suji, aida yon ken etc).
http://justanotherjapanesemahjongblog.b ... table.html
Also, there are many discard reading books about ura suji, aida yon ken, matagi suji on the market. You might be wondering, why hasn't there been any talk about discard reading. The reason is because according to game record statistics from 東風莊's super high level tables, this so called discard reading, do not affect the risk of related tiles. So when you're in betaori, it's better to ignore these "skills".
The only suji it describes is the basic one, so I was wondering about whether these strategies work.

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Scott Miller
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Re: Defending strategy: suji

Post by Scott Miller » Fri Sep 11, 2015 3:06 am

Mauro wrote:The only suji it describes is the basic one, so I was wondering about whether these strategies work.
There are far better players that can comment on strategy than me, but I can speak of my own personal experience, and for me, it would be disastrous if I were to start ignoring suji set clues.

Your quote references "super high levels" which might equate to Tenhou's 鳳凰 (Phoenix) room and higher. I'm not that high, so I wouldn't know. I would only predict that at that level of play, it's a whole new game.

But I can say without a doubt, in Tenhou's 特上 (Tokujō), for me, I rely heavily on the the suji and omote suji, and I think about ura suji only if I have nothing else to go on. By doing that, I've gotten to R1945. I don't think I could have gotten there without it.

I don't pay any attention to aida yon ken, or to matagi-sugi. Part of the reason I don't pay attention to these is that my brain is already busy enough as it is trying to look for the patterns I'm comfortable with in all three other discard piles simultaneously while the game is flowing, that there's little extra capacity for me to think about any new pattern comparisons I'm not yet comfortable with. Maybe that is ok, or maybe it's a weakness I need to work on. I won't know until I break through the R1950 ceiling, and look back and say, "That's what got me through."
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Re: Defending strategy: suji

Post by Gnom » Fri Sep 11, 2015 7:46 am

tl;dr: sujis work to some extent but are far from perfect. Refrain from using them if possible, if you don't have a choice they're better than nothing.

Omote suji, which si the most most basic type of suji allowing to identify potentially safe tiles without this much effort, feel like they definitely improve the ability to avoid dealing-in, if used properly (see after). Other types of suji feel like they can improve more slightly this rate, but their proper use can be trickier (both the actual reading and the times where you can rely on them)

What I mean about the proper use of suji is that you can never take what the tell you for granted, and in some situations you can know beforehand that they won't work. Suji allow you to see potentially safe and dangerous tiles based on your assumption that your opponents has a ryanmen wait (2-sided sequence wait), because it is the most efficient of basic waits so players are supposed to go after it. I think I saw some stats showing those waits represent about half of the waits of tenpai hands, so that's a pretty clear-cut majority and having that covered is pretty a good start. There's also the case where opponents are indeed aiming for ryanmen but couldn't make one, in which case suji may work to some extent since they follow the same logic as the one used by your opponent.

Now, it is possible that somebody doesn't have a ryanmen at all. They can even trick you, suppose that they have a 135 shape when they got to tenpai, they might discard the 5, which by omote suji would tell you the 2 is rather safe when it's actually their winning tile. It may also be that they're aiming for a yaku which doesn't allow this wait (toitoi for example.) or which makes you discard from a not so efficient way and may very well result in another type of wait (honitsu for example). You might look for these signs before deciding to trust sujis (a player making a pon, especially not a yakuhai one, or a discard indicating honitsu...) Also, beginners tend to "like" triplets and have some kind of erratic discard, meaning that suji is not likely to work with them.

Most importantly, suji should be used only as a last resort, either because you don't have safe tiles anymore or because you desperately need points and are looking at a potentially big win. Otherwise you should only use betaori (dealing only safe tiles at the cost of folding your hand). Sujis are a good tool but they are merely a lesser wrong.

Something more general: suji rely on the rules of efficiency. They are a formalization of some remarkable case. Knowing suji alone is not enough, before that you must be pretty good on tile efficiency. That's what allows you to pick up hints with sujis and see if the discard you're trying to read makes sense in that light. If you don't understand the big picture behind you won't use it properly even if you learn the dangerous and safe intervals yelled by each different type of sujis. Say for example you have a 49 aida yon ken. It may indicate that your opponent had a 4679 shape and kept the 67 only. Now if the player happens to have discarded a 3 before that it makes it less likely, because it means they threw away a 34 shape. In that case it's more likely they first discarded the 3 and when they got the 4 discarded it also. It doesn't mean your opponent doesn't have a 67 waiting for 58, but if they do it's just a coincidence. We can't pinpoint all the stuff that tells you that suji isn't accurate since there are so many , this is just an example of the thought process. And once again, the only way you can make that reasoning is to know efficiency yourself. At any rate that should be studied prior to suji also because building a hand efficiently allows to win more while sujis only allow you to lose less!

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Re: Defending strategy: suji

Post by Shirluban » Fri Sep 11, 2015 11:38 am

Suji and related discard reading techniques rely on the assumption players are playing according to tiles' efficiency and are specifically going for ryanmen waits.
And they only tell if a tile is probably safe or probably dangerous. They are not supposed to be 100% accurate, but only go give an edge from randomly discarding anything.

Before using suji, you should first guess which kind of hand an opponent is aiming for:
• Discards a lot of middle tiles and no or few honours? -> Looks like chanta / junchan -> the player is most probably not following tiles' efficiency.
• Discards only from two suits? -> half/full flush -> TE will be less relevant.
• Calls pungs, discards tiles already discarded? -> all pungs -> use a whole different TE and won't have a ryanmen.
• Closed hand, discards tiles already discarded, doesn't sort his tiles? -> seven pairs -> also a whole different TE and won't have a ryanmen.
• Riichi early? -> the hand was almost ready from the beginning -> didn't had time for TE.
• Beginner -> may not know about TE.

In all those situations, suji and the like are of little use, if any.
The reason is because according to game record statistics from 東風莊's super high level tables, this so called discard reading, do not affect the risk of related tiles.
I don't know about those statistics, but if they're computed blindly without taking into consideration the probability a player is following TE, then they're not relevant.
Without knowing how they are computed and analysed, I can't tell if it is gold or dung.
Say for example you have a 49 aida yon ken. It may indicate that your opponent had a 4679 shape and kept the 67 only.
It may also indicate your opponent had only 49 and no other tile in the suit.
But without better tips, 58 are slightly more dangerous than other tiles (and 49 are 100% safe).
It's all what suji and the like can tell: what is slightly safer and what is slightly more dangerous. Only discarded tiles are 100% safe, and you can never tell which tiles are the waiting ones.
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Re: Defending strategy: suji

Post by Iapetus » Fri Sep 11, 2015 6:51 pm

It's quite annoying that "suji" refers to two very different concepts: the 1-4-7 ("omote-suji") and the ura-suji stuff. Even in this topic, it's causing confusion and people trying to explain them together as one entity. There's way too many other "suji" words too - you may hear "uchisuji" or "tesuji" in Japanese speech.

"Omote-suji" or just "Suji", as explained on justanother, is a very important technique. Generally suji tiles are about half as dangerous as non-suji tiles. When defending, Suji tiles are your third line of defense after perfectly safe tiles and honors. When you're completely defending, that's exactly third. You do not discard suji tiles before perfectly safe tiles.

Suji factors greatly into attack/defense decisions as well. If you can remain in a good iishanten by discarding a suji tile, you often should. You can also use it to set traps. While 5 discard riichi from a 135 shape is not that good in high level play, it's still slightly better than a random kanchan. And for chiitoitsu, waiting on a 1 if you discarded the corresponding 4 earlier is very effective. There's a lot of applications, and you should learn to use them.

That was all for omote-suji. For ura-suji, matagi-suji and aida yon ken - as the statistics prove, they don't matter enough to be significant. You shouldn't waste brainpower thinking about them.

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Re: Defending strategy: suji

Post by Mauro » Sat Sep 12, 2015 8:51 am

Thanks for clarifying the terminology :D By saying "basic suji" I was referring to omote-suji, but I didn't knew the term (I saw it called suji-pai, but I'm not sure if it refers just to that or what).

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Re: Defending strategy: suji

Post by Shirluban » Sun Sep 13, 2015 9:24 am

"suji-pai" = suji tile ≃ suji
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