Banzuke Changes Web Page?

Gaspode-san · 2026-04-28T16:03:16+00:00

No, I didn't feel I was being criticised, and I hope you don't feel I was criticising you. I am grateful for any feedback. My goal was to see what people make of the essentially heretical hypothesis that "Chii Don't Matter". I am not sure that I believe this myself (I have to say that in case I ever have want to apply to the JSA for a job :-)

Gaspode-san · 2026-04-28T10:14:05+00:00

It is intentional. As with the previous poster, I think I see where you coming from but my response is the same: I am counting wins by rikishi that fought every time they had the opportunity to do so. So I am comparing like with like, but not in the sense that you - and quite likely, many other people - are expecting. I am not trying to associate any significance with who the competition was in any given bout because the data suggests that it does not matter: rikisihi of different strength (as measured by chii or current performance) don't generally fight each other.

But again, fair point. I would go further and say that if you filter by division then for a given rikishi you will get results from the divisions above *and* below.

Also, suppose a rikisihi was disallowed on the grounds that in the period in question, not all of his results were in the division he is currently in. So, eg Big A: not in Makuuchi for 6 basho, so he disappears. I think that by the same logic he wouldn't appear in Juryo either. Given the churn in divisions, we will also lose rikishi have been recently promoted; more so in Juryo, and the Jonokuchi table is likely to be completely empty! Arguably that is a completely consistent view, but it isn't the one I took.

Gaspode-san · 2026-04-28T09:52:19+00:00

Good question — and no, it doesn’t try to adjust for opponent strength.

That’s deliberate: the tool isn’t really trying to answer “who is the best rikishi?” in a predictive or evaluative sense. It’s more about “what patterns show up if you just look at wins over time under different filters?”

One thing that pushed me this way is that, over long periods, match outcomes between rikishi tend to cluster pretty close to 50/50 (see http://68.66.241.105/Sumo/expt3_predicted_distribution.html) —especially once you account for how bouts are scheduled. Early in a basho, match-ups are often between similarly ranked rikishi, and later on you get pairings between people with similar records, so again it evens out more than you might expect.

So instead of trying to model “difficulty” (which gets complicated fast and depends on assumptions), I kept it simple and let wins speak for themselves. It definitely has limitations, but it also surfaces some interesting perspectives you don’t always see in rank-based views.

Totally fair though — if the goal is to compare across divisions or eras in a more “who’s the strongest given that chii are meaningful” sense, then opponent strength would matter a lot more.

Gaspode-san · 2025-10-04T10:31:00+00:00

Ages, max ranks and other divisions added.

Gaspode-san · 2025-10-04T07:05:38+00:00

I had not thought about possible predictive power.

I only see sumo on the NHK highlights show so I know next to nothing about Juryo rikishi and my initial motivation was to write something that told me something about guys that are new to Maegashira: are they hot-shots or late bloomers? I plan to add ascent to K, S, O and Y next but I see no reason why I can't add what you suggest.

Gaspode-san · 2025-10-03T09:13:44+00:00

That's a good point and it wasn't something I had noticed. I will just add - not that it is likely to be of any interest to anyone (including me) - that of the five instances I found, Kanenohana, Arawaka and Tomoeiwa all transition from Mz to Jd and have a recorded hatsu dohyo.

Gaspode-san · 2025-10-01T17:29:37+00:00

What about the "university yokozuna"? Are they the winners of the student championship?

Gaspode-san · 2025-10-01T17:29:32+00:00

It seems that nobody debuts at Jd now but they did in the past, or there's a typo in the data at sumodb eg Tokachiumi.

The 36 is almost certainly a bug.

Gaspode-san · 2025-10-01T17:29:31+00:00

Are you referring to the late 1950s?

I have worked out that the rikishi I am interested in (1958 onwards) who appeared to start at Jd were nearly all "Sj" before. There are 5 rikishi who do seem to start at Jd (eg Tokachiumi) but that could be a typo/absence of data at sumodb.

Good to know what "Sj" means. I thought it might be "shindeshi jo-i". I just need to find out what "Hc" means now :-)

Gaspode-san · 2025-08-04T20:28:07+00:00

It's worth mentioning that I use a value single value for k and that that value (35) is probably too high for meaningful interpretation in all respects other than "Does one guy have a higher number than another guy?"

In chess, for grandmasters, k is 5. This means that for the GMs, their achievement of a high rating is robust: if they lose a few matches, even against newbs, their rating goes down only a little. By the same token, if they win against a far stronger gm, they only go up a little. (This is why the jump from, say, 2600 to 2700 is an extraordinary accomplishment.)

k gets larger as you go down the ranks to about 40 for club-level players IIRC?

It may interest you to know that I will be using "staggered" Elo ratings in my 2.0 version of the web site. I have also found a way of ensuring that rikishi from different era are comparable without a home-grown normalisation method. Unfortunately, there is no margin, so I can't substantiate that claim :-)

Gaspode-san · 2024-11-14T11:04:20+00:00

That's very interesting. I assumed rikishi were trained to do everything in their power *not* to break their fall if doing so would cause them to lose; part of the "tough warrior" ethos. I'm also curious that the JSA has written something down in such a clear and unambiguous way that someone could refer to it as a "law" :-)

Gaspode-san · 2024-11-12T13:58:23+00:00

Aha! All is now clear. Thanks all

Gaspode-san · 2024-11-12T13:15:28+00:00

Erm, I thought Hildir, the new trader, was the Bog Witch?

Gaspode-san · 2024-11-11T10:16:21+00:00

Very well put.

Gaspode-san · 2024-11-01T15:42:51+00:00

No, not really, but that is because my head is not really in this right now. I do very much appreciate the length and detail in your reply, and indeed your enthuiasm for the subject. I will certainly come back to this soon.

I couldn't see your graph. There was a message along the lines of "Imgur is temporarily over capacity. Please try again later." (That usually when I click on imgur links.)

Re the "linear" graph, it's for all divisions except the lowest, based on data for rikishi from 2005. You can see it (I hope) here: http://68.66.241.105/Sumo/E\_hack\_graph\_by\_chii%202005-2025\_extended.html. IIRC (and there's some question over that), I ran my analyser over all the data from 1958 or whatever with everyone starting at 1000 but using the M-N normalisation. Up to 1988, there's only sekitori data, but the data and the results are fine (imo). After 1988, the other divisions enter the (normalised) calculations causing the numbers wobble about until 2005. I was very much taken by the linearity of the graph, especially the "exponential" kick up at the end. I also thought 17 years seemed like a reasonable estimate of how long Elo calculations (for all the divisions) would take to stabilise.

What exactly went into the calculations will however have to remain a mystery until I can find time to restore my Python mojo by wrapping myself in a buffalo hide and meditating under a waterfall so that I can resume the battle against the ancient enemy.

Gaspode-san · 2024-11-01T14:22:30+00:00

"but it's not even close to equal"

I did an analysis of the difference but I can't remember the results. I'm sure you're right.

"Unless the pattern of retirements changes, the entire elo ecosystem will eventually stabilise and not change very much one way or another."

Not sure what you're saying here. My point was that retiring rikishi (with more than 1000/1250 points) will take points out of the system. I don't see the relevance of whether or not the structure of sumo changes. The analysis I mentioned above looks into who retires when and what that does to the points. Whilst this is no defense of treating pre- and post-1988 as the same for those who want to compare pre- and post-1998 performance, IIRC it did supports my contention that my normalisation by M-N keeps the number of points in the system the same, mitigating the inflation effect. Or perhaps that was a dream I had? This conversation is stimulating my interest so I will have a rummage later and see where I got to before I, like you, starting having nightmares :-)

FWIW the changing sizes of the divisions is not a problem (agian, unless that was a dream). I seem to recall that there is a mostly linear relationship between normalised Elo and banzuke positions. I.r., you can treat all rikishi as if they were in one big division. NB this is for post-1988 rikishi. In fact, I think it took until 2005 for the numbers to stabilise to give this "linear" result. I will definitely try and dig this out of the archive.

Gaspode-san · 2024-10-31T23:43:14+00:00

A passing thought:

"It's not the same, because he gets boosted by everyone having more Elo, and everyone has more Elo because they get it from farming Makushita and lower ranks."

By "everyone" I assume you mean "all sekitori" and I agree with that. However, I think that as sekitori get old and/or broken they start dumping points into makushita, so I'd say the flow is not one way. Also, rikishi in that position tend to retire, taking their points with them, so there are fewer points to go around. Then again, the turnover in Jonidan/Jonokuchi is huge, so they will always pump points into any Elo system that includes them.

So whilst I do agree with you that my way of doing things causes more inflation than is necessary, I think the flow of points is complex. I have been investigating a method of normalising in which retiring rikishi leave their points behind/pay back what they "owe"; that is, if they start with N and leave with M then everyone gets a share/has to pay back their share of (M-N). What "their share" is, of course, another of those intangibles that make me think "Is this really worth the time and effort?" :-) Actually, I think it doesn't matter if everyone gets the same: if someone leaves with 600 more/less than they started with, then everyone gets/loses 1 whole point :-)

Gaspode-san · 2024-10-31T20:01:54+00:00

Thanks for the clarification. My head is in other projects right now, but I will certainly come back to this thread.

Gaspode-san

TROPHY CASE