So according to Otonashi's website, what I was describing is "kongo" (mixed) uma and is a combination of standard uma and shizumi uma. Unless I'm mistaken, it's also what Senjo was describing. I think this means that we were both talking about something which was not "shizumi uma" itself as described on the page. That appears to be a system in which only first place receives points from people who are below the line.

I really don't know how popular either of these rules is in Japan. The only large body I've heard of that employs them is pro renmei, which uses "kongo" uma. I've never heard of anyone else using either and have never seen any non-standard uma employed in parlors I've been at.

Also, from looking at Tsunoda's original post, it seems like there's a hierarchy of ideas; certain rules will be implemented, other are under various levels of consideration. I'm still not sure what form of shizumi uma he intended to refer to.

I don't know the details of Benjamin's earlier comment, but I think it is not misinterpretation. There are some different style "shizumi uma".

Although there are some different style "shizumi uma" , I wouldn't say correct rule ," but "shizumi uma" I wrote and explained is commonly known thing in Japan. Apparently this rule is popular in Osaka and west Japan.

http://www.hakata21.com/suzume/5zats/umatable.html

there are many "Uma"
the style Senjo mentioned "1 over.2 over ..." this kind of sizumi uma rule is in this page.

Then again, maybe Otonashi and I are referring to the same thing. I kinda wish Otonashi he would post in Japanese so I can be sure.

Shizumi-uma is usualy simple payment. when your score is 30100 , you dont need to pay.
How much you have to pay is NOT depend on your order and the mumber of players.
all under 30000 players have to pay same amount and only 1st player get everything.

so this means ,3 players under 30000 is best for 1st player.
only 1 player under 3000 is worst for 1st player.

Or is it an unequal payment dependent on place and the 30000 mark, like:
1 over:
1st = +30k
2nd = -5k
3rd = -10k
4th = -15k

2 over:
(same as normal: +20k, +10k, -10k, -20k)

3 over:
1st = +15k
2nd = +10k
3rd = +5k
4th = -30k

In any case, thanks for posting about shizumi-uma and okuri-kan.

Shizumi Uma : If the Break even point, is 30000, when you point is under 30000, you have to pay "Shizumi Uma". All minus score players have to pay it.

Okkurikan is ,　you know, After Riichi you can do "no-changed winning tiles KAN(An-KAN)" Okkurikan is almost same. the difference is "no-changed win tiles" but "changed structure in hand" usually prohibited to do this Okurikan.

for exsample:

WW RRR 555567 (12)

Tsumo 8 ,If you do KAN , your winning Tiles are (3),not change
but ww RRR 5555 678 (12), the Structure is changed, new 678 coming up.