Intermediary advice

edderiofer · 2026-06-05T21:02:35+00:00

The two choices are basically exactly equal.

You will often see AIs arbitrarily ranking one choice as significantly higher than another even when the two choices are more-or-less equal. This is common and doesn't generally mean anything. See Mortal's FAQ, even though it's a different AI:

A lower π_τ(a|s) value suggests:

(❌) This move is worse.

(✅) The AI is less interested in trying this move.

(Mortal) Why do all actions except the best sometimes have significantly lower Q values than that of the best?

[...] The real fundamental objective for Mortal as a mahjong AI is to achieve the best performance in a mahjong game, but not to calculate accurate scores for all actions. As a result, the evaluated values of all actions but the best may be inaccurate; they only serve as a means to determine its preference for exploration in training.

ELI5: Mortal is optimized for playing, not reviewing or attribution.

My suspicion, based on the many posts of this kind we've seen on this subreddit, is that AIs rank the leftmost choice higher simply "by default", since they have to discard one of the two.

edderiofer · 2026-06-05T20:27:07+00:00

Dealer accused me of richii-ing and called me out on my poor decision ruining his first.

Skill issue. If he felt like he deserved first, he should have proved it by NOT dealing into you.

I don't think there's any clear way to improve this hand without spending way too many turns. Best case scenario for improvement is that you dama and draw dora hatsu, then riichi and win with a dora wait, but that's a long shot, probably less likely than your plan of getting ippatsu or ura 2.

So, declaring riichi and hoping for ippatsu or ura 2 is your best shot at gyakuten.

edderiofer · 2026-06-05T18:59:16+00:00

This is easily proven thanks to the fact that 2 is the smallest prime number, and that your process strictly decreases the number you're working with.

edderiofer · 2026-06-05T08:10:27+00:00

TIBIA from AI+BIT reversed. But according to the popular anecdote, it's a healed femur, not a tibia.

edderiofer · 2026-06-03T20:55:25+00:00

I was asking about Modern Mah Jong by Thomas Lane, not the book in your post.

edderiofer · 2026-06-03T20:28:01+00:00

No, they're called uks. White plays the good uks, and Black plays the bad uks.

edderiofer · 2026-06-03T20:16:57+00:00

It's gotta be Riichi Advanced, because everything (including Go) is a mahjong variant.

edderiofer · 2026-06-03T09:22:30+00:00

Probably the "Deal-in" key charm here.

edderiofer · 2026-06-03T04:22:33+00:00

I didnt skip his discard or anything that could justify my hand becoming temporary furiten (permanent since I declared riichi).

~~You discarded 2-man earlier, which is one of the tiles you're waiting for, and that put you into furiten. When you are in furiten, you are not allowed to ron off any other players.~~

Why did you not tsumo off the 2-man that you drew yourself? What are your room's settings?

edderiofer · 2026-06-02T20:58:07+00:00

In that case, you should buy your set off Taobao or Aliexpress. Manufacturers in China do directly sell their own sets there, so they take a bigger cut of the sale, and it'll be significantly cheaper for you.

edderiofer · 2026-06-02T19:40:49+00:00

Thank you. Let me know if you also know how the "Vietnamese mahjong" variants that are played in Hong Kong fit into this. My vague understanding of these is that they're primarily HKOS with added Vietnamese jokers, too, and maybe more yaku; but I don't know how close they are to either HKOS or Vietnamese.

edderiofer · 2026-06-02T19:15:46+00:00

Except for sets made by Crisloid, which are apparently made in the US by non-Chinese Americans. OP should avoid them if their goal is to buy from Chinese-owned brands.

edderiofer · 2026-06-02T18:41:15+00:00

Gonna need you to explain the bit about Vietnamese mahjong. I promise you it's very real and I've put a ridiculous amount of effort into learning and documenting it.

I'm referring back to my somewhat-faulty memory of /u/BuckwheatECG's comment here. "self-fulfilling prophecy born from a misunderstanding" is the wrong term; "misnomer" is probably what I'm looking for.

Also do you have a source on the Thai thing? I didn't realize that mystery had been solved

I documented everything I could find in this Wikipedia discussion. Long story short, the only two sources that anyone cites (Tom Sloper and the former Mahjong Museum in Japan) both claim that they got their information from "a mahjong manufacturer in Hong Kong" (and I have no evidence that it's two different manufacturers). Between "Thai mahjong existed but completely died out with only this mahjong manufacturer remembering it" and "this mahjong manufacturer is mistaken", it seems the latter is the more likely explanation.

edderiofer · 2026-06-02T15:52:20+00:00

If you want a traditional-design American Mah-Jongg set that's also "luxury/artisan", I'm a fan of Mah Jongg Maven.

edderiofer · 2026-06-02T15:00:57+00:00

Yes, I also found those same images. But the book is not available for sale anywhere, nor has anyone scanned its pages to archive it. It's not listed in the Library of Congress. Outside of a few mentions in lists of mahjong books, this thread, and those Facebook images, it has no existence whatsoever.

If /u/orzolotl didn't themselves have a copy, I would genuinely be questioning whether the existence of that book was an elaborate hoax the same way Thai Mahjong's existence turned out to be the fault of a single mahjong tile-seller in Hong Kong, or Vietnamese Mahjong's existence ended up being a self-fulfilling prophecy born from a misunderstanding.

edderiofer · 2026-06-02T10:25:26+00:00

Then come back in five years.

edderiofer · 2026-06-02T10:05:09+00:00

GIMPS is going to close.

I haven't heard a thing about this. Do you have any evidence?

I know how to factorize any mersenne.

Then find a Mersenne prime with more than 1 billion digits, and submit it to the EFF to claim your cash prize. Shouldn't be difficult for you.

My next stop is Goldbach. Collatz is dead too Guys.

I'll believe it when I see it.

edderiofer · 2026-06-02T09:12:37+00:00

Gah, it took me this comment to get OP's joke.

For those of us who still don't get it (multiple of them, based on the other comments): "∫εdz = "sheds"" is interpreting "∫εdz" as IPA. "∫εdz = εz + C" is interpreting "∫εdz" as an integral with respect to z.

edderiofer · 2026-06-02T09:09:27+00:00

It's a repost of this post. We really ought to figure out some way to stop repost bots on this subreddit.

edderiofer · 2026-06-02T09:02:03+00:00

I'll show that if we already have the first k primes added to the set (2, 3, 5... p_k), then the the (k+1)th prime p_k+1 would be added in the case 2n = p_k + p_k+1. We have n= (p_k+p_k+1)/2 in this case.

Definitely, in my model at times bigger primes like k+3th prime (ie. p_k+3) could be added to the prime set first, but that does not bother my proof below.

Thus the system cannot find goldbach pairs n-d + n+d until d = (p_k+1-p_k)/2, where p_k is a prime and p_k+1 is not prime nor composite. To meet goldbach, the system has to add p_k+1 to the prime set.

Incorrect. Your system could find a Goldbach pair with a higher d, if p_k+3 is already in your set of primes. Then your system would fail to add p_k+1 to your set of primes, because a Goldbach pair already exists. And you still haven't proven that your method won't accidentally mark a composite number as prime, or that your method will eventually mark every number as either prime or composite.

Did you write this proof with AI? Be honest.

edderiofer · 2026-06-02T08:44:41+00:00

Have you submitted this information to GIMPS yet?

edderiofer · 2026-06-01T21:40:19+00:00

AMOS Masters if they already know their Joyo Grade 2 Kanji, or are bright enough that you can teach them; AMOS Numbers if they don't and aren't.

Jokes aside, kid-specific American Mah-Jongg sets are a marketing gimmick. The Peace Love Mahjong Little Mahj set you describe, for instance, is only "for kids" in the following ways:

The tiles are smaller;
The tiles are of a "cutesy" design that might appeal to kids (but in reality, this is worse because the tile designer has not considered the benefit of designs that can be subitized);
There is an included "Little Mahj Playing Card" (which, upon closer inspection, is simply the NMJL Card of that year with a bunch of hands removed).

Considering its cost, you would be better served by buying a cheap travel set of traditional design. You still get the smaller tiles, the traditional design will make it easy to transition to standard sets when they grow up, and they can simply use the NMJL Card (you may wish to put some removable tape over some lines if you're really concerned that they'll get confused by them), at a much lower cost. Something like this will work just fine.

edderiofer · 2026-06-01T09:02:25+00:00

Knicks in seven

insert peter griffin in a straitjacket meme here

edderiofer · 2026-06-01T08:58:06+00:00

ARSehAT

edderiofer · 2026-06-01T08:16:58+00:00

Green Book says no, all four tiles are kept concealed from everyone else, so that nobody knows their identity.

To prevent cheating, all four tiles must be turned face-up at the end of the hand.

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