Heirarchy of Two-Sided Waits

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Heirarchy of Two-Sided Waits

Post by HotelFSR » Sun Apr 26, 2009 10:35 pm

Question:

Would it be correct to assume that, from best to worst, two-sided waits are ranked in three tiers like so:


1-4 and 6-9

2-5 and 5-8

3-6 and 4-7


Presumably you want to have either terminals or 2/8 as part of your wait because they are the most likely to come out?

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Re:Heirarchy of Two-Sided Waits

Post by Looper » Mon Apr 27, 2009 2:07 am

I\'d never really thought about that, but it sounds reasonable. If you assume more tiles closer to the middle will be incorporated into players\' hands, it\'s better to wait on tiles farther out.

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Re:Heirarchy of Two-Sided Waits

Post by HotelFSR » Mon Apr 27, 2009 9:50 am

Yeah. It occurred to me when Ben Boas mentioned on another thread here that a 5-8 wait is marginally better than a 4-7 wait. I\'m assuming this is why.

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Re:Heirarchy of Two-Sided Waits

Post by Monadology » Mon Apr 27, 2009 1:50 pm

Interesting, I hadn\'t thought about this.

Red Fives can only be used in 3-6 and 4-7 waits (unless one is waiting on a five of course) which makes the choice of the number 5 for a bonus tile make a bit more sense, I suppose.

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Re:Heirarchy of Two-Sided Waits

Post by Ruro » Mon Apr 27, 2009 1:54 pm

yea this seems to be right, but i don\'t think that 2-5 and 5-8 are sooo better than 3-6 and 4-7. I might be a bad player but i like to throw away the 1-9\'s all the way in the game (except at the endgame). And there are many factors i think, like if the 4 or 5 becomes a dora then the tiles around that will almost likely stay in the players hands. And if there is the red 5 rule then the 5 is an unlikely tile to be dealt of waited for...

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Re:Heirarchy of Two-Sided Waits

Post by Shirluban » Tue Apr 28, 2009 12:16 pm

Ruro wrote:i like to throw away the 1-9\'s all the way in the game
That\'s why a wait on 1 or 9 is more likely to go out than other waits.


You should know some tiles are more useful than others.
Honors can\'t be used in chii.
1 and 9 can be used only in 123 (789) chii.
2 and 8 can be used in 123 and 234 (789 and 678) chii.
3, 4, 5, 6 and 7 can be used in 123, 234 and 345 chii.
(I don\'t speak about pon, kan and pairs since there is no difference on it.)

So we can sort tiles from the most useful to the less :
3, 4, 5, 6, 7
2, 8
1, 9
Honors

There is also a difference between 3/7, 4/6 and 5 but let this off for now.
The plot is:
- For attack, in doubt, it\'s better to throw Honors and 1/9 first (and next 2/8) and keep other tiles which are more likely to be used.
- For defence, Honors and 1/9 (and next 2/8) are safer, since opponents are less likely to use it (for a chii, a 7 can be used in 3 ways, where a 9 can be used only in 1).
-> Whatever, players are most likely to throw an honor, an 1/9, or a 2/8 than other tiles. So a wait on 1-4/6-9 is more likely to go out than a wait on 2-5/5-8, who is more likely to go out than a wait on 3-6/4-7.

From the best-better to the less-better :
1-4 (_23_) / 6-9 (_78_)
2-5 (_34_) / 5-8 (_67_)
3-6 (_45_) / 4-7 (_56_)


Basing on this hierarchy of 2-side waits, we can review the hierarchy of tiles\'s usefullness.
2-side waits with a 3/7 are globaly better than waits with a 4/6 who are globaly better than waits with a 5.
From the high usefullness value, to the low usefullness value :
3, 7
4, 6
5
2, 8
1, 9
Honors
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Re:Heirarchy of Two-Sided Waits

Post by Ruro » Tue Apr 28, 2009 11:24 pm

hmm you know i\'ve been thinking, and maybe its a bit off topic, but wouldn\'t thinking (too much) with the \"two sided\" mindset is kinda dangerous? Doesn\'t this just dull you, and maybe(just maybe) backfires at the most inconvenient moment?

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Re:Heirarchy of Two-Sided Waits

Post by HotelFSR » Tue Apr 28, 2009 11:53 pm

Ruro:


Most of the time you want to build two sided waits and defend against them as your first priority. Statistically this is the most efficient strategy and is the basis of good play. However, as you point out, not every wait you face is going to be two-sided.

Bear in mind that you can still sometimes guess when you are up against a single wait. For example, early reaches are often not two sided, and you will notice that some players (either due to risk style or being ahead/behind) will simply be more willing than others to reach on single waits. This is particularly true in games with good players, where one may feel sure that they can reach and cause someone to fold, second guessing them with a single wait. Of course, this can backfire if the opponent does not fold and fights back with a two sided tenpai.

Whenever you suspect a single wait you can play it safe and avoid using furiten defense methods. In live games you may even be able to detect a bluff.

Finally, there are ways of detecting other waits from the discard patterns but this is extremely advanced and only worth trying in very high level play. There\'s an article on this site by Konno where he gives an example of how you might detect a shanpon wait!

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Re:Heirarchy of Two-Sided Waits

Post by Looper » Wed Apr 29, 2009 3:13 am

Finally, there are ways of detecting other waits from the discard patterns but this is extremely advanced and only worth trying in very high level play. There\'s an article on this site by Konno where he gives an example of how you might detect a shanpon wait!
I\'ll admit here, I mainly picked up mahjong from watching Akagi. I remember in the first match of the show how they were talking about the \"back vein\" of his main opponent\'s pool - Akagi discarded a tile that was a likely part of his two-sided wait, but he knew that it wasn\'t really his wait. I\'m sure that sort of strategic thinking takes a lot of play and experience to get down.

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Re:Heirarchy of Two-Sided Waits

Post by HotelFSR » Wed Apr 29, 2009 9:45 am

True.

Bear in mind, though, that as fun as Akagi is you should not use it as a reference on real Mahjong. The concepts of luck and statistics shown in the show are completely ridiculous and not based on reality.

While it is certainly possible to read waits that are not two sided, it is seldom 100% reliable.

Most reading is a process of elimination that becomes easier when there have been a greater number of discards. For example, let\'s say an opponent discards a 3s out from his hand. You might think that\'s indicating an ura-suji (back vein, 4-7 wait), and then later the same opponent discards a 7s. That rules out the 4-7 and instead points to a 5-8 on the basis of the original 3 being a senki-suji and the 8 being a matagi-suji. Don\'t count on it though, what if the 3 was in fact the matagi-suji? These things are harder to judge online when you cannot look closely at the movement of tiles in the opponents hand.

You also want to watch for the possibility that one of the suits is just \'noise\' and is not being used at all! Often this is suggested when you see another player make a risky discard against reach, which passes safely. You can probably shift your focus to other suits in this case.

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Re:Heirarchy of Two-Sided Waits

Post by Shirluban » Wed Apr 29, 2009 12:25 pm

Ruro:

It\'s true two-side waits are not all, but let\'s see some other kind of waits:

- Single wait (pair wait) and dual pon wait (i.e. having two pairs and waiting to turn one of them into a pon) :
You can\'t realy defend against this, expext by counting which tiles remain in play.

- Middle wait :
The winning tile can be any tile from 2 (1_3) to 8 (7_9).
It can\'t be waiting for an honor or a 1/9.
So it concords with the usefullness value table I\'ve given.
(I may have not said yet a high usefullness value indicates not only a useful tile to keep but also a risky tile to discard.)

- Terminal wait (i.e. waiting on 12_ or _89) :
It\'s not a very frequent wait, but still show the most usefull tiles 3/7 to be dangerous.

- Floting pair wait (e.g. having 1234 and waiting for 1 or 4) :
From a strategic point of view, it works just like two-sided waits.



In conclusion, many kinds of waits exist (and I\'ve not listed all of them) and opponents may wait with another thing than a two-side wait. But they all show middle tiles to be better than terminals.
The usefullness value hierarchy is not an absolute rule but a general guideline of tiles to keep/throw in priority.
I\'ve not shown it here, but two-sided waits are the best easy waits (except rare case of waiting on 3 or more tiles).

So you can rely on the theory your opponents will generaly go for two-side waits and tiles from the riskier to the safer are generaly 3/7 > 4/6 > 5 > 2/8 > 1/9 > honors.
It can backfire, but the gain outwight the risk.

You should also know than dora and red fives (aka dora) alter tiles\' usefullness values.
And sometimes, players\' current strategy go backward from this (traps, bluff, chanta/junchan, kokushi, ...).
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Re:Heirarchy of Two-Sided Waits

Post by Looper » Thu Apr 30, 2009 3:05 am

Ha, I can\'t use Akagi as a reference for playing style at all. I\'m no Akagi.

The irritating thing about online play, at least on Tenhou, is that you can\'t tell whether your opponents are dealing their draws or from their hands.

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Re:Heirarchy of Two-Sided Waits

Post by HotelFSR » Thu Apr 30, 2009 8:57 am

Haven\'t played on Tenhou for a while, but I\'m pretty sure you can.

You may not be able to see where in the hand the tile came from, but I think the animation is different depending on whether it\'s a draw-discard or hand-discard.

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Re:Heirarchy of Two-Sided Waits

Post by Looper » Thu Apr 30, 2009 10:24 pm

I just noticed. Man, I must be blind.

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Re:Heirarchy of Two-Sided Waits

Post by HotelFSR » Thu Apr 30, 2009 11:49 pm

I think Ron2 may be the only site that shows where in the hand a discard comes from.

Or can you see this on Tenhou too?

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