Comments on: Let’s Debunk Some Mahjong Superstitions!

By: SedoKai

SedoKai — Mon, 31 Oct 2011 03:24:38 +0000

Math and Statistics are cute, but only scratch the surface of the game. If anything, having a solid understanding of the mathematical aspect of the game is merely a basic requirement to improving beyond beginner-level play.

By: xKime

xKime — Tue, 12 Jan 2010 04:22:44 +0000

I would really like to see a graph representing “turn number of riichi” in function of “average value of the hand.” Of course I have a pretty good idea what it will look like, but who knows when it will display some surprising/mildly interesting data.

By: drob(inVienna)

drob(inVienna) — Sat, 25 Jul 2009 07:30:24 +0000

That’s…

Eh. Whatever. Too tired to think.

By: Sumio Mondo

Sumio Mondo — Fri, 24 Jul 2009 22:39:30 +0000

well, yeah, but not if you combine it with what that article showed (the one i linked from reachmahjong.com).

also, like i said, sometimes you have no choice but to make defensive decisions based on assuming ryanmen-waits. pulling out these things is an edge you will occasionally want to exploit if you simply have no safer options.

i also wonder whether the frequency of ryanmen reaches increases if you filter out early-turn reaches and such. i think you can also at times sense when you are up against non-ryanmen waits because the discards don’t make ‘sense’ as they usually do (basically an extension of what is mentioned in the article).

By: umai

umai — Fri, 24 Jul 2009 17:04:58 +0000

I think that it would be a mistake to assume there is a 1 in 4 chance every time when the statistics showed an overall 1 in 3 chance. The problem is that you can get a 1 in 4 chance only under unknown conditions, so to just blindly assume them means you’ll still get bitten 1 time in 3.

By: Sumio Mondo

Sumio Mondo — Fri, 24 Jul 2009 13:02:26 +0000

One more point: the strategy can be more or less effective defending on the player. Some people almost always only reach when they have ryanmen. Depends how much of a read you have.

Obviously there will never be a failsafe reading strategy in a game like this but every little edge can help.

By: Sumio Mondo

Sumio Mondo — Fri, 24 Jul 2009 12:59:45 +0000

Actually i think you can build a strategy around it-

i.e. if you want to fold completely, throw 100% safe tiles as far as possible.

However, if you have to resort to suji reading (such as 1-4-7) and all related methods, you might as well consider that the reach-tile suit is only dangerous in 1 out of 4 times.

This is simply because you’ll be assuming that the wait is ryanmen by default, if you are going to bother with suji reading. Don’t use it if you can help it, but sometimes you have no other choice.

Now, if you can combine this with actually spotting when a wait is not ryanmen, then you’re really onto something.
Here’s a link to the article I mentioned concerning that:

http://www.reachmahjong.com/home/index.php?option=com_content&task=view&id=344&Itemid=127

You might want to read the previous article to review the questions posed.

By: drob(inVienna)

drob(inVienna) — Fri, 24 Jul 2009 09:15:22 +0000

Yeah; it’s just superstitions – there’s no real way for us to look at the riichi tile and say “Ok, that suit is safe.” Hell, I’d go so far as to say that it’s safer to discard the idea completely than base a strategy around it/incorporating it into current tactics.

By: umai

umai — Thu, 23 Jul 2009 21:01:49 +0000

Might be on to something here. Here’s the statistics for riichis on ryanmen-like waits only:

2744 riichis
725 had a wait in the same suit
Ratio: 26.421%

You can see why a strategy for spotting ryanmen waits is important here. Even though a large number (71%) of the riichis were on ryanmen-like waits, we can’t tell they are ryanmen waits in-game with such certainty. That makes any strategy that could come of this useless as long as the overall probability of there being a wait in some suit is 1 in 3. Any ideas?

By: umai

umai — Thu, 23 Jul 2009 19:42:38 +0000

Hmm, I removed tsumokiris as well, didn’t seem to make much of a diference though.

3841 riichis
1240 had a wait in the same suit
Ratio: 32.283%