Strength of Yūshō

[Seiyashi 4,108]

I'm sorry to present yet another inane stats thread with no real thesis, but this doesn't contain as much writing, I swear!

While I'm on the DB scraping train, I've put together a table displaying yūshō scores since 1950, together with their sum of opponent score (SOS), to provide some sort of means of assessing yūshō. Some yūshō were less gimmes than we thought (they might still have been based on rank). For instance, Tokushōryū's makujiri yūshō in Hatsu 2020 had a SOS of 120, definitely above average for yūshō. Conversely, Hakuhō's last yūshō in Nagoya 2021 had a SOS of 97, pretty low, and considering how shaky he looked that basho, having slightly tougher opponents might well have handed Terunofuji the Emperor's Cup instead. Some of Takanohana's yūshō were also very cheap, unsurprising considering what we know about the circumstances of the joi at the time.

Overall, the vital stats are as follows:

• Maximum: 131 (M5e Kotonishiki, Aki 1991 and M14e Tamanoumi, Kyūshū 1957)
• Minimum: 85 (Y1e Takanohana, Hatsu 1995)
• Mean: 111.40 
• Standard deviation: 6.74
• Median: 110
• Mode: 110

For those who want to screw around with the data in raw normalised form yourselves, the GSheets link is as follows: https://docs.google.com/spreadsheets/d/1cZXTA90Q95L9qmfex4IJ20LlsRZam3GcaLD26Nsng0M/edit?usp=sharing. There's a lot of follow-ups possible, like which yokozuna averaged the highest strength of opponent schedule, which yūshō that led to promotions were cheap, etcetc, but we'll see what comes up in reactions to this.

(Also as an aside in case the DB folks are looking - yes, the 1 page/s rate works fantastically. Very few access errors if at all.)

And lastly, the table:

	1	3	5	7	9	11
2022	S1e Mitakeumi 13-2(116)	S1e Wakatakakage 12-3(119)	Y1e Terunofuji 12-3(118)
2021	M1w Daieisho 13-2(118)	S1e Terunofuji 12-3(117)	O2w Terunofuji 12-3(117)	Y1e Hakuho 15-0(97)	Y1w Terunofuji 13-2(103)	Y1e Terunofuji 15-0(115)
2020	M17w Tokushoryu 14-1(120)	Y1e Hakuho 13-2(113)		M17e Terunofuji 13-2(127)	S1e Shodai 13-2(108)	O1e Takakeisho 13-2(115)
2019	S1w Tamawashi 13-2(110)	Y1e Hakuho 15-0(103)	M8w Asanoyama 12-3(116)	Y1e Kakuryu 14-1(121)	S1e Mitakeumi 12-3(114)	Y1w Hakuho 14-1(111)
2018	M3w Tochinoshin 14-1(117)	Y1e Kakuryu 13-2(111)	Y1e Kakuryu 14-1(111)	S1w Mitakeumi 13-2(111)	Y1w Hakuho 15-0(110)	K1e Takakeisho 13-2(109)
2017	O1e Kisenosato 14-1(107)	Y2w Kisenosato 13-2(106)	Y2w Hakuho 15-0(106)	Y1e Hakuho 14-1(107)	Y1w Harumafuji 11-4(113)	Y1w Hakuho 14-1(117)
2016	O2e Kotoshogiku 14-1(116)	Y1w Hakuho 14-1(115)	Y1e Hakuho 15-0(110)	Y2e Harumafuji 13-2(119)	O2e Goeido 15-0(118)	Y1w Kakuryu 14-1(110)
2015	Y1e Hakuho 15-0(107)	Y1e Hakuho 14-1(114)	S1e Terunofuji 12-3(111)	Y1e Hakuho 14-1(112)	Y1w Kakuryu 12-3(120)	Y2e Harumafuji 13-2(112)
2014	Y1w Hakuho 14-1(114)	O1e Kakuryu 14-1(103)	Y1e Hakuho 14-1(109)	Y1e Hakuho 13-2(104)	Y1e Hakuho 14-1(107)	Y1e Hakuho 14-1(114)
2013	Y1w Harumafuji 15-0(110)	Y1w Hakuho 15-0(110)	Y1e Hakuho 15-0(108)	Y1e Hakuho 13-2(112)	Y1e Hakuho 14-1(114)	Y1w Harumafuji 14-1(111)
2012	O1e Baruto 14-1(106)	Y1e Hakuho 13-2(109)	M7w Kyokutenho 12-3(116)	O2w Harumafuji 15-0(118)	O1e Harumafuji 15-0(119)	Y1e Hakuho 14-1(111)
2011	Y1e Hakuho 14-1(111)		Y1e Hakuho 13-2(112)	O1w Harumafuji 14-1(111)	Y1e Hakuho 13-2(118)	Y1e Hakuho 14-1(105)
2010	Y1w Asashoryu 13-2(114)	Y1e Hakuho 15-0(108)	Y1e Hakuho 15-0(105)	Y1e Hakuho 15-0(112)	Y1e Hakuho 15-0(111)	Y1e Hakuho 14-1(120)
2009	Y1w Asashoryu 14-1(106)	Y1w Hakuho 15-0(107)	O1w Harumafuji 14-1(120)	Y1e Hakuho 14-1(107)	Y1w Asashoryu 14-1(103)	Y1w Hakuho 15-0(108)
2008	Y1e Hakuho 14-1(110)	Y1w Asashoryu 13-2(112)	O2w Kotooshu 14-1(107)	Y1w Hakuho 15-0(107)	Y1e Hakuho 14-1(113)	Y1e Hakuho 13-2(117)
2007	Y1e Asashoryu 14-1(108)	O1w Hakuho 13-2(119)	O1e Hakuho 15-0(104)	Y1e Asashoryu 14-1(107)	Y1w Hakuho 13-2(118)	Y1e Hakuho 12-3(115)
2006	O2e Tochiazuma 14-1(116)	Y1e Asashoryu 13-2(115)	O3w Hakuho 14-1(121)	Y1e Asashoryu 14-1(105)	Y1e Asashoryu 13-2(115)	Y1e Asashoryu 15-0(113)
2005	Y1e Asashoryu 15-0(115)	Y1e Asashoryu 14-1(110)	Y1e Asashoryu 15-0(109)	Y1e Asashoryu 13-2(116)	Y1e Asashoryu 13-2(119)	Y1e Asashoryu 14-1(108)
2004	Y1e Asashoryu 15-0(115)	Y1e Asashoryu 15-0(113)	Y1e Asashoryu 13-2(115)	Y1e Asashoryu 13-2(108)	O1e Kaio 13-2(115)	Y1e Asashoryu 13-2(117)
2003	O1e Asashoryu 14-1(111)	O2e Chiyotaikai 12-3(118)	Y1e Asashoryu 13-2(111)	O1e Kaio 12-3(119)	Y1e Asashoryu 13-2(119)	O1w Tochiazuma 13-2(117)
2002	O2w Tochiazuma 13-2(114)	Y1e Musashimaru 13-2(111)	Y1e Musashimaru 13-2(108)	O1w Chiyotaikai 14-1(111)	Y1e Musashimaru 13-2(111)	O2e Asashoryu 14-1(106)
2001	Y2e Takanohana 14-1(116)	O1e Kaio 13-2(118)	Y1e Takanohana 13-2(114)	O3e Kaio 13-2(119)	M2e Kotomitsuki 13-2(120)	Y1e Musashimaru 13-2(112)
2000	S2e Musoyama 13-2(109)	M14e Takatoriki 13-2(129)	K1w Kaio 14-1(124)	Y1e Akebono 13-2(113)	Y1w Musashimaru 14-1(103)	Y1w Akebono 14-1(113)
1999	S1e Chiyotaikai 13-2(123)	O1e Musashimaru 13-2(109)	O1e Musashimaru 13-2(115)	S1w Dejima 13-2(120)	Y1w Musashimaru 12-3(109)	Y1e Musashimaru 12-3(101)
1998	O1w Musashimaru 12-3(108)	O2e Wakanohana 14-1(103)	O1e Wakanohana 12-3(100)	Y1w Takanohana 14-1(100)	Y1e Takanohana 13-2(104)	M12w Kotonishiki 14-1(122)
1997	O1e Wakanohana 14-1(103)	Y1e Takanohana 12-3(104)	Y1w Akebono 13-2(105)	Y1e Takanohana 13-2(105)	Y1e Takanohana 13-2(91)	O1w Takanonami 14-1(106)
1996	O2e Takanonami 14-1(101)	Y1e Takanohana 14-1(99)	Y1e Takanohana 14-1(108)	Y1e Takanohana 13-2(99)	Y1e Takanohana 15-0(97)	O1w Musashimaru 11-4(105)
1995	Y1e Takanohana 13-2(85)	Y1w Akebono 14-1(113)	Y1w Takanohana 14-1(112)	Y1e Takanohana 13-2(109)	Y1e Takanohana 15-0(109)	O1w Wakanohana 12-3(106)
1994	O1w Takanohana 14-1(110)	Y1e Akebono 12-3(115)	O1w Takanohana 14-1(106)	O1w Musashimaru 15-0(105)	O2w Takanohana 15-0(102)	O1e Takanohana 15-0(101)
1993	O1e Akebono 13-2(115)	K1e Wakahanada 14-1(108)	O1e Takanohana 14-1(106)	Y1e Akebono 13-2(117)	Y1e Akebono 14-1(113)	Y1e Akebono 13-2(115)
1992	M2e Takahanada 14-1(117)	O1e Konishiki 13-2(118)	S1w Akebono 13-2(119)	M1w Mitoizumi 13-2(120)	K1w Takahanada 14-1(122)	O1w Akebono 14-1(114)
1991	O1e Kirishima 14-1(114)	Y1e Hokutoumi 13-2(113)	Y2eHD Asahifuji 14-1(120)	M13e Kotofuji 14-1(124)	M5e Kotonishiki 13-2(131)	O1w Konishiki 13-2(111)
1990	Y1e Chiyonofuji 14-1(100)	Y1w Hokutoumi 13-2(108)	O2wHD Asahifuji 14-1(110)	O1e Asahifuji 14-1(107)	Y2eHD Hokutoumi 14-1(107)	Y2eHD Chiyonofuji 13-2(107)
1989	Y2eHD Hokutoumi 14-1(104)	Y1w Chiyonofuji 14-1(106)	Y2eHD Hokutoumi 13-2(110)	Y2eHD Chiyonofuji 12-3(111)	Y1w Chiyonofuji 15-0(106)	O2wHD Konishiki 14-1(114)
1988	O1e Asahifuji 14-1(116)	Y2eHD Onokuni 13-2(107)	Y2eHD Chiyonofuji 14-1(107)	Y1e Chiyonofuji 15-0(110)	Y1e Chiyonofuji 15-0(111)	Y1e Chiyonofuji 14-1(107)
1987	Y1e Chiyonofuji 12-3(103)	O1w Hokutoumi 12-3(105)	O1w Onokuni 15-0(120)	Y1e Chiyonofuji 14-1(104)	Y1w Hokutoumi 14-1(106)	Y2eHD Chiyonofuji 15-0(96)
1986	Y1e Chiyonofuji 13-2(120)	S1w Hoshi 13-2(119)	Y1e Chiyonofuji 13-2(103)	Y1e Chiyonofuji 14-1(108)	Y1e Chiyonofuji 14-1(105)	Y1e Chiyonofuji 13-2(107)
1985	Y1e Chiyonofuji 15-0(103)	O2eHD Asashio 13-2(113)	Y1e Chiyonofuji 14-1(114)	O2eHD Hokutenyu 13-2(115)	Y1e Chiyonofuji 15-0(107)	Y1e Chiyonofuji 14-1(108)
1984	Y1w Takanosato 13-2(107)	O1e Wakashimazu 14-1(105)	Y1w Kitanoumi 15-0(110)	O2eHD Wakashimazu 15-0(113)	M12w Tagaryu 13-2(123)	Y1w Chiyonofuji 14-1(108)
1983	O1w Kotokaze 14-1(122)	Y1e Chiyonofuji 15-0(114)	S1e Hokutenyu 14-1(109)	O1e Takanosato 14-1(105)	Y1w Takanosato 15-0(100)	Y1w Chiyonofuji 14-1(111)
1982	Y1wYO Kitanoumi 13-2(121)	Y1w Chiyonofuji 13-2(112)	Y1e Chiyonofuji 13-2(118)	Y1e Chiyonofuji 12-3(114)	O1w Takanosato 15-0(100)	Y1e Chiyonofuji 14-1(113)
1981	S1e Chiyonofuji 14-1(121)	Y1e Kitanoumi 13-2(102)	Y1e Kitanoumi 14-1(116)	O1e Chiyonofuji 14-1(125)	S1e Kotokaze 12-3(119)	Y2eHD Chiyonofuji 12-3(115)
1980	Y1e Mienoumi 15-0(109)	Y1w Kitanoumi 13-2(109)	Y1e Kitanoumi 14-1(105)	Y1e Kitanoumi 15-0(108)	Y1w Wakanohana 14-1(108)	Y2eHD Wajima 14-1(115)
1979	Y2eHD Kitanoumi 14-1(104)	Y1e Kitanoumi 15-0(105)	Y1w Wakanohana 14-1(106)	Y2eHD Wajima 14-1(111)	Y1w Kitanoumi 13-2(108)	Y1wYO Mienoumi 14-1(111)
1978	Y1w Kitanoumi 15-0(117)	Y1e Kitanoumi 13-2(104)	Y1e Kitanoumi 14-1(106)	Y1e Kitanoumi 15-0(112)	Y1e Kitanoumi 14-1(106)	Y1w Wakanohana 15-0(111)
1977	Y1w Wajima 13-2(113)	Y1w Kitanoumi 15-0(115)	O1w Wakamisugi 13-2(116)	Y1w Wajima 15-0(112)	Y1w Kitanoumi 15-0(108)	Y1w Wajima 14-1(107)
1976	Y1e Kitanoumi 13-2(113)	Y1w Wajima 13-2(125)	Y1w Kitanoumi 13-2(120)	Y1e Wajima 14-1(121)	M4w Kaiketsu 14-1(125)	Y1w Kitanoumi 14-1(120)
1975	Y1e Kitanoumi 12-3(113)	O1e Takanohana 13-2(119)	Y1e Kitanoumi 13-2(124)	M1w Kongo 13-2(110)	O1w Takanohana 12-3(115)	S1e Mienoumi 13-2(122)
1974	S1e Kitanoumi 14-1(124)	Y1e Wajima 12-3(117)	O1e Kitanoumi 13-2(116)	Y1e Wajima 13-2(125)	Y1e Wajima 14-1(108)	K2wHD Kaiketsu 12-3(124)
1973	O1e Kotozakura 14-1(115)	Y1w Kitanofuji 14-1(118)	O1e Wajima 15-0(109)	Y1w Kotozakura 14-1(120)	Y2eHD Wajima 15-0(102)	Y1e Wajima 12-2-1(109)
1972	M5w Tochiazuma 11-4(114)	S1e Hasegawa 12-3(114)	S1w Wajima 12-3(119)	M4e Takamiyama 13-2(122)	Y1e Kitanofuji 15-0(114)	O2wHD Kotozakura 14-1(117)
1971	Y1w Taiho 14-1(89)	Y1e Tamanoumi 14-1(109)	Y2eHD Kitanofuji 15-0(101)	Y1w Tamanoumi 15-0(106)	Y1w Kitanofuji 15-0(113)	Y1e Kitanofuji 13-2(120)
1970	O1e Kitanofuji 13-2(111)	Y2eHD Taiho 14-1(101)	Y1w Kitanofuji 14-1(109)	Y1e Kitanofuji 13-2(110)	Y1w Tamanoumi 14-1(111)	Y1e Tamanoumi 14-1(111)
1969	Y1e Taiho 15-0(108)	O2eHD Kotozakura 13-2(120)	Y1w Taiho 13-2(116)	O1e Kiyokuni 12-3(116)	O2wHD Tamanoshima 13-2(113)	O1w Kitanofuji 13-2(110)
1968	Y1e Sadanoyama 13-2(116)	M8e Wakanami 13-2(113)	O1e Tamanoshima 13-2(101)	O2wHD Kotozakura 13-2(112)	Y1w Taiho 14-1(110)	Y1e Taiho 15-0(111)
1967	Y1e Taiho 15-0(105)	O1e Kitanofuji 14-1(103)	Y1e Taiho 14-1(104)	Y1w Kashiwado 14-1(114)	Y2eHD Taiho 15-0(110)	Y1w Sadanoyama 12-3(108)
1966	Y2wHD Kashiwado 14-1(116)	Y2eHD Taiho 13-2(109)	Y1e Taiho 14-1(114)	Y1e Taiho 14-1(107)	Y1e Taiho 13-2(110)	Y1e Taiho 15-0(105)
1965	O1e Sadanoyama 13-2(102)	Y1e Taiho 14-1(116)	Y1w Sadanoyama 14-1(110)	Y1w Taiho 13-2(111)	Y2eHD Kashiwado 12-3(115)	Y2eHD Taiho 13-2(110)
1964	Y1e Taiho 15-0(105)	Y1e Taiho 15-0(108)	Y2eHD Tochinoumi 13-2(96)	M9w Fujinishiki 14-1(121)	Y1w Taiho 14-1(102)	Y1e Taiho 14-1(114)
1963	Y1e Taiho 14-1(113)	Y1e Taiho 14-1(107)	Y1e Taiho 15-0(103)	O3eHD Kitabayama 13-2(113)	Y1w Kashiwado 15-0(116)	O1w Tochinoumi 14-1(109)
1962	Y1e Taiho 13-2(99)	S2eHD Sadanoyama 13-2(122)	S1w Tochinoumi 14-1(96)	Y1e Taiho 14-1(96)	Y1e Taiho 13-2(115)	Y1e Taiho 13-2(120)
1961	O1w Kashiwado 13-2(119)	Y1w Asashio 13-2(115)	M13w Sadanoyama 12-3(123)	O1e Taiho 13-2(122)	O1e Taiho 12-3(118)	Y1w Taiho 13-2(110)
1960	Y1e Tochinishiki 14-1(119)	Y2eHD Wakanohana 15-0(121)	M4w Wakamisugi 14-1(111)	Y1e Wakanohana 13-2(121)	Y1e Wakanohana 13-2(115)	S1e Taiho 13-2(111)
1959	Y1e Wakanohana 14-1(112)	Y1w Tochinishiki 14-1(114)	Y2eHD Wakanohana 14-1(113)	Y1e Tochinishiki 15-0(109)	Y1wYO Wakanohana 14-1(115)	O1e Wakahaguro 13-2(113)
1958	O1e Wakanohana 13-2(107)	O1e Asashio 13-2(111)	Y2eHD Tochinishiki 14-1(98)	Y2eHD Wakanohana 13-2(113)	Y1e Wakanohana 14-1(109)	O1w Asashio 14-1(98)
1957	Y2wHD Chiyonoyama 15-0(100)	S1w Asashio 13-2(115)	K1w Annenyama 13-2(104)		Y1e Tochinishiki 13-2(117)	M14e Tamanoumi 15-0(131)
1956	Y1e Kagamisato 14-1(116)	S1e Asashio 12-3(121)	O1e Wakanohana 12-3(112)		Y1w Kagamisato 14-1(106)
1955	Y1e Chiyonoyama 12-3(113)	Y1e Chiyonoyama 13-2(121)	Y1w Tochinishiki 14-1(105)		Y1w Kagamisato 14-1(100)
1954	O1e Yoshibayama 15-0(101)	O1e Mitsuneyama 12-3(108)	O1w Tochinishiki 14-1(111)		O1e Tochinishiki 14-1(99)
1953	O1e Kagamisato 14-1(107)	O1e Tochinishiki 14-1(119)	M6e Tokitsuyama 15-0(106)		Y1w Azumafuji 14-1(104)
1952	Y2eHD Haguroyama 15-0(107)		Y2wHD Azumafuji 13-2(112)		S1w Tochinishiki 14-1(110)
1951	Y1e Terukuni 15-0(114)		O1e Chiyonoyama 14-1(114)		Y1e Azumafuji 13-1-1a(103)
1950	O1e Chiyonoyama 12-3(119)		Y1w Azumafuji 14-1(112)		Y2eHD Terukuni 13-2(122)

Edited June 10, 2022 by Seiyashi

[Sakura 1,495]

As you point out, rank should make a difference. An opponent who ends up with a score of 10-5 from M14 is probably not at the same difficulty-level as an opponent who scores 10-5 as an Ozeki.

Furthermore, by doing really well a rikishi would lower their SOS. Let's say in a basho that the Jun-Yusho line was 12-3 when the yusho was 15-0. Instead of going zensho, the yusho winner could have gone 12-3 with a playoff win instead. That's three more wins for our winner with a zensho, but three more losses for his opponents (and consequently a lower SOS for our yusho winner).

Given that you are disregarding rank (reasonable, since a highly injured Ozeki or Yokozuna may not be the strongest opponent one would have to face), then I would suggest a slight modification. Give something like 2pt for a win, 1pt for beating  rikishi with double digits and 1pt for beating a rikishi with at least 13 wins. So a yusho winner who beat a 14-1 rikishi would score 4pts for that victory (win + double-digits + at least 13 wins). You could also subtract 1pt for every time our yusho winner beat a rikishi who had double-digit losses, or similar. So beating a 5-10 rikishi would net you 1 point instead of 2.

[Seiyashi 4,108]

1 hour ago, Sakura said:

Furthermore, by doing really well a rikishi would lower their SOS. Let's say in a basho that the Jun-Yusho line was 12-3 when the yusho was 15-0. Instead of going zensho, the yusho winner could have gone 12-3 with a playoff win instead. That's three more wins for our winner with a zensho, but three more losses for his opponents (and consequently a lower SOS for our yusho winner).

If I understand my sources correctly, the way to sort this out is actually to do a full Buchholz scoring by multiplying by the rikishi's own score. The current method is really only suited for tiebreak purposes - i.e. comparing scores of the same number where that multiplication wouldn't make a difference. However, that's a lot less intuitive to look at, so while it would appropriately differentiate the zenshō from the 12-3 D by showing an increase in the SOS by 25%, it would be less easy to use that number straightaway as a means of comparing opponents. It would more accurately reflect how impressive the yūshō was in terms of the opponents beaten and the score eventually achieved.

As an aside, I know from my brief dive into said sources regarding ratings that there are a lot of different systems out there each with their own strengths and weaknesses. Any others that might be relevant at this point?

[Tsuchinoninjin 1,276]

I would take a 2 year window of results for each rikishi for the basho in question, and calculate the decayed history rating for each. Then the strength of yusho would just be the average decayed history rating of defeated opponents. This would take into account situations where lower makuuchi is pretty strong just by luck (some guys from joi sitting out due to injury in previous basho plus some young star coming up from juryo or something) that would be obscured by using just rank or SOS.

Decayed history rating did pretty well at the various sumo games - better than I did with my own brain (though I'm kind of dumb just fyi)

[Taliesin 68]

Yeah, not accounting for opponents ranks at all won't do. If one wants to calculate strength of the opposition which does not have any Y or O among them, I'd say just look at their positions at the next banzuke. Of course it's not the case when talking about makuuchi yuusho, but there are still some viable methods, e.g. just like counting for promotion/demotion purposes -  Rank+score.

[Gurowake 4,109]

There are many things wrong with this type of analysis.

First, when assessing strength of schedule in this way, you need to factor in to each rikishi's score their own win-loss record.  The main reason for this is to get around the effect of winning more meaning that your opponents lose more.  The best way to do this is to ignore the matches the rikishi himself was in, so basically subtracting from the total the number of losses that he had.  You could alternately add his own wins to the total, but if you're looking at win percentage of the opponents, this skews it towards 50%, as it's counting a win and loss both for the matches the rikishi himself was in.

Second, it also doesn't really compare well when considering the effect of withdrawals.  Sometimes the withdrawal means the rikishi was hobbling coming in, but sometimes it means they got hurt during the tournament.  A Yokozuna who wins their first match but gets hurt in the process should be considered a better opponent than average, not the same as one that got only 1 win (See Harumafuji, Nagoya 2015).

Third, it's only really comparable when rikishi have the same sort of opponents, and the main difference you're measuring is in which rikishi were not fought because they withdrew or were the same heya.  It's not comparable when you have a mid-to-low maegashira in the mix, since their general grade of opponent is going to be lower. 

How would I improve this?  One way to measure the quality of the opponent would just be by rank.  If you wanted a source of points by rank, there's the RotoSumo schedule of points per win by rank readily available.  I'm sure it's not perfect, but it's a start.  Another would be to do a ratings engine and get some measure of how strong each rikishi is that way, and then measure the expected wins for a rikishi of constant quality against the winner's slate of opponents   The problem with ratings engines (besides the work that goes into building one) is that they are prone to either deflation or inflation, as their main goal is to rate players against their contemporaries, not against their predecessors, and it's impossible to know whether this inflation is due to a real increase in strength or just a fluke of the rating system.  You could normalize the ratings every so often, but that forces the assumption that average strength never changes.  At best you'll be able to see which Yusho were relatively harder or easier compared to those surrounding them, though it wouldn't necessarily work comparing Yusho from decades apart.  

 

Edited June 10, 2022 by Gurowake

[SDM 9]

It is a complicated thing.
First you look at the opponents results to get SOS.
But then one opponents 9-6 is not the same as another persons 9-6 so how to diffrentiate?
You could look at that person's opponents SOS to weight the input but it seems like a vicious circle.
Plus we haven't then taken into account the issue of feedback error [aka double counting] because the initial persons's reslut is in a sense double/triple counted.
Then should we also consider rank not just results alone but that opens up another can of worms about people struggling with injuries etc.
Ultimatley we have to accept that there is no one true method.
Whatever method we choose it is a matter of choice/opinion about what is apropo.
Still it would be interesting to see the results of these studies to help us to make our choices.
We just shouldn't see it as ultimate proof.

[Jejima 1,427]

4 hours ago, SDM said:

Anyone remember the old Sumo mailing list from the previous millenium? 

Off topic, but I have just read your tagline. Not only do I remember the old Sumo Mailing list of the previous decade, I am still on it - and yes, there is still traffic - but nowhere near what it once was. 

[SDM 9]

48 minutes ago, Jejima said:

Off topic, but I have just read your tagline. Not only do I remember the old Sumo Mailing list of the previous decade, I am still on it - and yes, there is still traffic - but nowhere near what it once was. 

Ironically I dropped off that list back then because I was far out of reach in various parts of Japan for an extended period without access to online.

[Yamanashi 3,908]

About a year ago I started one of many unfinished projects, looking at the "strength" of a basho in terms of career high ranks: that is, not only the Y's and O's, but the future Y's and O's and S's, etc.  Obviously, you can't do this for this year's or last year's basho, but you can go back, say 10 years and find out (in retrospect) what an awesome batch of career-wise awesome wrestlers were present at that basho.

I am out of town and working on other things right now, but I remember clearly that the most awesome basho, going back to ~2000, was the Natsu 2008 tournament won by Kotooshu (go figure!).  I will attempt to find my spreadsheet in a week or so when I am back in town.  IIRC I took career high ranks and then awarded points for Yokozuna (10), Ozeki (8), etc.  That sounds like the SOS approach you may be talking about here.

Someday after I retire, I may finish all these projects and post them as a set.  That should scare away a good number of forum members.

[Reonito 1,530]

1 hour ago, Yamanashi said:

I am out of town and working on other things right now, but I remember clearly that the most awesome basho, going back to ~2000, was the Natsu 2008 tournament won by Kotooshu (go figure!).

Going by career-high rank, I count 5 yokozuna and 4 ozeki on his fight card. And his only loss was to Aminishiki.

[Jakusotsu 6,052]

5 hours ago, Yamanashi said:

Someday after I retire, I may finish...

I guess @Asojima is laughing the loudest.

[Asojima 2,874]

11 hours ago, Jakusotsu said:

I guess @Asojima is laughing the loudest.

Retirement is a good starting point for all those projects that have been sitting on the back burner.  Those projects lead to new ones.