open pinfu (jumbo shrimp)

[Ignatius]

Seven pairs: 25 fu.
Kuipin / open pinfu / horizontal exposed hand / (some other unholy translation): 30 fu.
Closed pinfu+tsumo: 20 fu.
Everything else: 20 base fu plus...

If we can accept that seven pairs with three value pairs is 25 fu, and not 31 or 40 fu, then we can put anything related to kuipin right up there before even talking about how blabbity blah blah...

Yeah, but at least Seven Pairs can be 2 Han 25 Fu, or 1 Han 50 Fu...

[Referee]

Yeah, but at least Seven Pairs can be 2 Han 25 Fu, or 1 Han 50 Fu...

Which it may seem so but it is NOT equivalent. IMHO, 50-1 for Chiitoi is apocryphal, and just an unnecessary simplification of calculations. Because now... Menchin Chiitoi? 25-8 (baiman), or 50-7 (haneman)?

[Ignatius]

Yeah, but at least Seven Pairs can be 2 Han 25 Fu, or 1 Han 50 Fu...

Which it may seem so but it is NOT equivalent. IMHO, 50-1 for Chiitoi is apocryphal, and just an unnecessary simplification of calculations. Because now... Menchin Chiitoi? 25-8 (baiman), or 50-7 (haneman)?

You're right with that point, pal.

[Senechal]

Again, just because a videogame has it in an option doesn't mean it's worth referencing. I appreciate that others can view the rules to standard ari-ari mahjong as being more complex than other games they usually play, up there with Twilight Imperium. I don't think it's wise to scatter bait by derailing with comments about how chiitoitsu is 1:50 on XYZ videogame and I think one of the minor pro leagues has it as such.

[Shirluban]

The only way to score 20 fu is to have a closed pinfu hand won by tsumo.
And that's because 1) we don't count the 2 fu for tsumo in this case (to ensure valueless hands are valueless); 2) any other valueless hand gets 2 fu, thanks to "open pinfu" (so it's not valueless any more).
That's not really coherent, but it's the rule.

So, the 20 fu ron line should not be there.
(Unless they have a different scoring?)

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Counting Chitoi 1 han 50 fu doesn't even simplify the scoring: as long as the fu are not cumulative, it's still an exception. It only simplify the scoring table.
Counting it 2 han 25 fu has the advantage to make the exception stand out more, so it's not forgotten.

[Referee]

What I meant is that it simplifies the calculation, if done by head. If you go by charts, I agree it's not a simplification. Anyway, I agree it should be 25-2.

[or2az]

Wouldn't you know that 4 days after this discussion, at my weekly mahjong event with the ladies I've been teaching, one of them had an open tanyao of chows with a double-sided wait and a simple pair. After I added the points to be 30 and 1, she asked why it wasn't 20 and 1.
I confidently said (like I knew the answer all the time), that "since japanese rules require a closed no-points hand to get a double (yaku), they generously give a 2 pt bonus (which gets rounded up) for an open one provided you get another double to go along with it".
Whew, just in time. It went over ok....and actually made sense. Thanks guys.

[Ignatius]

Good lucky day for you then...