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Jakusotsu

Number of wins for yusho in Juryo (split from Sumo articles)

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1 hour ago, Jakusotsu said:

One simple statistical reason for the average number of wins for Juryo yusho being lower than for Makunouchi is the smaller size of the division.

Doesn't make obvious sense on the face of it right? All the rikishi still fight on 15 days. There being 14 less rikishi doesn't seem to have any bearing on the number of wins you can get, which is presumably based on the skill differential. 

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Posted (edited)
2 hours ago, Jakusotsu said:

One simple statistical reason for the average number of wins for Juryo yusho being lower than for Makunouchi is the smaller size of the division.

I'm not following... Nearly all yusho winners are in the joi, and their opponents are other members of the joi, which is actually a smaller range of ranks than a typical juryo schedule.

By far the bigger factor is that rikishi good enough to 15-0 in juryo, are usually not in juryo anymore. Unless I'm missing something.

Edited by yohcun
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1 hour ago, yohcun said:

By far the bigger factor is that rikishi good enough to 15-0 in juryo, are usually not in juryo anymore.

And no matter how good you are, you can't get promoted out of makunouchi. That means that the ability range is much wider in the top division. No-one really bats an eyelid when someone from the bottom end of the juryo ranking yushos: in the last two tears we've had wins from two J11s, a J12, a J13 and a J14. Mind you, that's becoming a thing in maku'uchi in 2020.

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1 hour ago, yohcun said:

By far the bigger factor is that rikishi good enough to 15-0 in juryo, are usually not in juryo anymore. Unless I'm missing something.

To be more precise, rikishi good enough to 15-0 in juryo are in top form compared to their contemporaries. Even if they 15-0 in juryo, they still score a 15-0 in juryo, so the question is why only particular rikishi have done it, and, more damningly, why not only the best (e.g. why Hakuho, Asashoryu, Kitanoumi and other ichidai-toshiyori tier yokozuna have not done it).

The two most famous recent examples are Tochinoshin (good enough to make komusubi previously, recovering from dropping to makushita, logging 4 yusho in a row and the last with a 15-0 juryo yusho), and Baruto (one of the fastest risers to makuuchi, 15-0 after an enforced rest due to appendicitis, and only in his 12th honbasho (including maezumo). Even so, sumodb only contains 5 examples of a 15-0 in juryo, so drawing on a small sample size, I'd hazard a guess that it's down to creating a huge performance differential due to better rest, more motivation, higher skill, etcetc (certainly explains Tochinoshin and Baruto, but not Kitanofuji, who was in Juryo for 2-3 tournaments before his 15-0, and took another 7 years to reach yokozuna, so he wasn't exactly blazing it).

I'd say juryo has a scrappier arasoi because it's predominantly filled with rikishi who aren't of the calibre (whether physical or mental) to cut it in makuuchi, and up-and-comers getting used to a 15-day schedule. So for both these reasons, rikishi will drop bouts when they otherwise wouldn't.

8 minutes ago, Tigerboy1966 said:

And no matter how good you are, you can't get promoted out of makunouchi.

 

3 hours ago, Jakusotsu said:

One simple statistical reason for the average number of wins for Juryo yusho being lower than for Makunouchi is the smaller size of the division.

But these two come in to explain why zenshos are rarer in juryo versus either makuuchi (76) or lower divisions (almost 3k over all 4 divisions, averaging to about 750 per division) (there's a distinction between rarity of zenshos and the yusho score). Tigerboy's explanation covers the case of yokozuna just blazing it, whereas the sheer number of rikishi in the lower divisions and the lesser number of bouts means that by simple happenstance, more rikishi will wind up with 7-0s than sekitori with zenshos.

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Posted (edited)

Not taking any particular strength comparison into account but assuming a normal distribution of wins, a larger population is likely to produce a bigger amplitude.

If you throw three dice 42 times, the probability for a zensho to come up is higher than when you throw only 28 times.

Edited by Jakusotsu

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1 minute ago, Jakusotsu said:

Not taking any particular strength comparison into account but assuming a normal distribution of wins, a larger population is likely to produce a bigger amplitude.

If you throw a 15-sided die 42 times, the probability for a zensho to come up is higher than when you throw only 28 times.

I'd be interested in an explanation of how that works. To me, it seems counter-intuitive that 'throwing the die' just 14 more times per basho should increase the probability of a zensho by a factor of 15 (~76/5).

I've always assumed the lower winning scores in juryo are due to the make-up of the division; i.e. former hiramaku on a slow decline, a few whose peak is juryo level, and up-and-coming youngsters. The experience of the first two tends to counter the vigour and inexperience of the youngsters. 

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I'll take "All of the Above" for $500, Alex.

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3 minutes ago, RabidJohn said:

I'd be interested in an explanation of how that works. To me, it seems counter-intuitive that 'throwing the die' just 14 more times per basho should increase the probability of a zensho by a factor of 15 (~76/5). 

Of course that normal distribution model is far too simplified (yielding only a factor of 1,5 if you do the maths), but it still matters for some small part.

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I am reminded of the famous quote by Samuel Langhorne Clemens: "There are lies, damned lies, and statistics."

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Posted (edited)

Hold up, we're discussing two different things here.

The first is the probability of a zensho in juryo, whereas the second is why a juryo yusho generally scores lower than a makuuchi yusho.

Re the probability of a zensho in juryo, I agree that purely probabilistically, the lowest number of rikishi in Juryo means that we're less likely to see a zensho compared to other divisions. But I disagree with that premise because it doesn't seem sound to assume that every juryo rikishi is the same in fighting power, experience, and motivation such as to create the 50-50 conditions that give rise to the above probabilistic assumption. 

1 hour ago, RabidJohn said:

I've always assumed the lower winning scores in juryo are due to the make-up of the division; i.e. former hiramaku on a slow decline, a few whose peak is juryo level, and up-and-coming youngsters. The experience of the first two tends to counter the vigour and inexperience of the youngsters. 

I'm gonna have to go with @RabidJohn here to back up what I said about juryo being a hot mess.

Re why a juryo yusho generally scores lower than a makuuchi yusho - going back to the 15-day schedule (since 1950 for the first full year), the breakdown of yusho scores in juryo and makuuchi is as follows (no juryo yusho with 9-6, no makuuchi yusho with 10-5):

  1. 15-0Y: 5J, 73M
  2. 14-1Y: 22J, 157M
  3. 13-2Y: 81J, 133M
  4. 12-3Y: 140J, 38M
  5. 11-4Y: 117J, 3M
  6. 10-5Y: 38J, 0M
  7. 9-6Y: 1J (Buyuzan, 2001 Nagoya; thanks to @Flohru and @Wamahada)

Makuuchi sees more 14-1s than any other score, whereas juryo sees more 12-3s than any other score. So this does bear out the common wisdom that it's "easier" numerically to yusho in juryo than makuuchi. But juryo yusho winners rarely look as good as yokozuna when doing it. As to why the yusho profile for juryo is lower than makuuchi, I think the simplest explanation is also that advanced by @RabidJohn regarding the quality of juryo rikishi.

But the normalish distribution of the juryo yusho results as opposed to the makuuchi results does suggest an alternative statistical explanation to me. if I were to try and explain this mathematically, making assumptions about the nature of rikishi's fighting strength, I'd say that the fighting strength of juryo rikishi, represented in terms of results, is more likely to be normally distributed (because of the already discussed factors). In contrast, makuuchi by its very nature is much more likely to be artificially capped at the strongest rikishi on the banzuke at any one time. In other words, if I were to arbitrarily extend a tournament to allow for sheer attrition, maybe Hakuho would start losing on day 25, Asashoryu on day 23, Kitanofuji on day 20, Harumafuji on day 18.... but that doesn't happen, so they are effectively undefeated for the duration of a honbasho. Whereas in juryo, relatively fewer rikishi are of that sheer power compared to their opponents, therefore will start losing earlier.

 

 

Edited by Seiyashi
Brain fart
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8 minutes ago, Seiyashi said:

 the breakdown of yusho scores in juryo and makuuchi is as follows (no juryo yusho with 9-6, no makuuchi yusho with 10-5):

  1. 15-0Y: 5J, 73M
  2. 14-1Y: 22J, 157M
  3. 13-2Y: 81J, 133M
  4. 12-3Y: 140J, 38M
  5. 11-4Y: 117J, 3M
  6. 10-5Y: 38J, 0M 

 

Don't tell that to Buyuzan!

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Posted (edited)
17 minutes ago, Seiyashi said:

 (no juryo yusho with 9-6, no makuuchi yusho with 10-5):
 

 

 

Buyuzan yushoed with 9-6 the Nagoya 2001 Basho in Juryo

Edited by Wamahada
formal reason

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I think a possible analogy would be like having sand, water, and oil in two vessels of different heights (volumes), and then you stir it. With the same/similar stirring force (torikumi within 7-8 ranks or so), it's easier to mix things in the smaller vessel (juryo) than the big one (makuuchi). So the stratification/separation in makuuchi is more pronounced.

And of course, the top dogs don't stay long in juryo and so this reduces their chances of scoring a juryo zensho.

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Mostly because a really good rikishi will not stay in juryo for long. However, as someone had said, rikishies like Asashoryu or Hakuho will not be promoted out of Makuuchi.

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In the short time that I have been watching Juryo matches, I have found it to be a division of parity and entertaining or frustrating unpredictability--about Day 10 of every basho I decide that there just isn't any way I can predict what Akiseyama will do and start picking the opposite of what my instinct says.  :)  It is quite common for there to be a huge Juryo tie for the lead a few wins above average at any point.  The competition at both ends, to go up to the top division, and to avoid loss of salary and silk mawashis, is what keeps this division so exciting, even if the sumo is not quite as impressive as the top division.   It was a very curious decision to come to: most hierarchial leagues have a slightly larger second division than top division; sumo seems to have decided that the answer to the ultimate question -- how many rikishi must be in the top division? -- is 42, and then went on to decide that the next division down should be one-third smaller, and the chaos below that can balloon to hundreds.  The result is that we usually have some competitive action to watch even when Hakuho is looking invincible at the top.  A six-way playoff is a bit extreme, but absolutely characteristic.

Bill James once pointed out that the bell curve has little to do with the distribution of talent in baseball, because the bell curve describes a complete population, and the subset of pro ballplayers is the extreme right edge of that graph, where there isn't a lot of space but it extends forever.  If you eliminate those ballplayers, or rikishi, who are less than 2.5 standard deviations from the population mean, you get a different distribution, where there is no real limit on talent level but a slight skew to the lower end within that range of "extremely good" to "virtually unbeatable."  Juryo is that small band at the lower end of the elite, +2.5 to +2.75 SD.  All the real freaks are up in the top division or soon will be.  And the existence of the freaks who are +4 or +5 or +6.7 SD from the mean are the reason why Juryo yushos are winnable with 11 wins and Makuuchi needs 13 or 14 minimum. 

 

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26 minutes ago, Ichimawashi said:

It was a very curious decision to come to: most hierarchial leagues have a slightly larger second division than top division...

Historically, makushita was the (very much) larger second division, and the juryo were the top few wrestlers in makushita (a reference to how much they were paid - 10 ryo). 

Also the number of rikishi in makuuchi was not always the answer to the meaning of life and everything.

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I wonder what the name of an ultra-elite 7th division would be...any suggestions?

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42 minutes ago, Katooshu said:

I wonder what the name of an ultra-elite 7th division would be...any suggestions?

Sanyaku.  :-P

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3 hours ago, Ichimawashi said:

the answer to the ultimate question

Life, the universe and sumo.

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2 hours ago, Katooshu said:

I wonder what the name of an ultra-elite 7th division would be...any suggestions?

Sounds like when the so-called “big clubs” of European football threaten to withdraw from their respective domestic competitions and start a new elite pan-European league where they keep all the money and hoover up all the best players. 

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9 hours ago, Katooshu said:

I wonder what the name of an ultra-elite 7th division would be...any suggestions?

Dunno about the division name but the members would be called ojikata and post intai they will be called ojiikata instead of oyakata (Beardeddisguise...)(Beardeddisguise...)

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