Natsu Banzuke Prediction Post-mortem


Two key criteria for developing good predictions are: (1) quantitative evaluation of the prediction and (2) accountability. With that in mind, I take a look at how my banzuke prediction performed.

Upper San’yaku was “chalk” as expected. In the lower San’yaku, I (and other predictions on this site) correctly had Yoshikaze filling the komusubi slot vacated by Shodai. I don’t understand the order of the three sekiwake ranks, as it appears unchanged despite the very different performances at Haru that had all of us predicting the order as Takayasu 1E, Kotoshogiku 1W and Tamawashi 2E.

In the maegashira ranks, of the 31 predictions, I had 11 “bulls-eyes” (correct rank and side” and 3 more correct rank predictions. This is way fewer than I expected or would have liked. The 17 misses were mostly not too bad: 13 missed by one rank, 3 missed by two ranks, and I had Osunaarashi (J1) moving up to M16 and Myogiryu (M15) dropping to J1.

There are three parts to the prediction: the computed ranks, tie-breaking among rikishi with identical ranks, and the departures I make from the computed ranks based on past banzuke patterns. Let’s look at these in turn.

The computed ranks were quite accurate: the official banzuke departs from these in only a couple of places. The computed rank would have Takarafuji at M3, but because of his make-koshi at that rank at Haru, the prediction and the banzuke moved him down to M4. Shodai (one of my two-rank misses) should be down at M7, and I still feel like the NSK cut him way too much slack after his 4-11 performance. And Arawashi and Ishiura would switch sides (but not ranks).

My tie-breaker was higher rank at Haru. This largely resulted in both of my other two-rank misses, as Takanoiwa should have been ranked above Tochiozan (and Aoiyama) by this rule. Presumably his 6-9 record at Haru led to his being dropped further down, although this is not necessarily consistent with past banzuke patterns. In a number of other cases, the tie-breaker got the relative order right, and I will need to look closely to see if the tie-break part of the prediction can be improved.

So, on to the departures from the computed rank order. One rule that resulted in many of my misses was to drop rikishi with 7-8 make-koshi records one spot from their rank at Haru, even if the computed rank would have them retaining their rank. This has often (but not always) been done in past banzuke. Although this rule correctly placed Takarafuji at M4, it placed Kagayaki, Tochinoshin, Ishiura and Daishomaru one slot too low, which also led to one-rank misses in the other direction for Ura, Arawashi, Kotoyuki and Onosho. It seems that the NSK is inconsistent in this scenario, and I’ll have to see if any pattern can be identified.

So overall, I am happy with my computed ranks, need to think more about the tie-break procedure, and need to be more careful with subjective departures from the computed ranks (this also includes demoting Myogiryu in favor of promoting Osunaarashi, even though Myogiryu had a better computed rank).

Others can chime in with how they fared. There will be another opportunity to predict the Nagoya banzuke after Natsu is the in books, and in the meantime we’ll have some actual sumo to watch!

Guess the Natsu Banzuke 2.0


In my previous guest post, I made predictions for the Natsu banzuke right after the conclusion of the Haru basho. With the release of the official Natsu banzuke only 10 days away, I thought I’d update my predictions, based partly on the feedback I received from Tachiai readers. In addition to pointing out the inherent unpredictability of the banzuke due to subjective NSK committee decisions, commenters noted that the committee tends to favor higher-ranked rikishi over lower-ranked ones to a greater extent than my predictions did. With that in mind, here is a second attempt at the Natsu banzuke.

Rank East West
K Mitakeumi Yoshikaze (3)
M1 Chiyonokuni (3) Endo (4)
M2 Okinoumi (3) Chiyoshoma (4)
M3 Daieisho (4) Takanoiwa (5)
M4 Takarafuji (4) Aoiyama (5)
M5 Takekaze (6) Ikioi (6)
M6 Tochiozan (5) Hokutofuji (6)
M7 Shodai (7) Takakeisho (6)
M8 Shohozan (8) Sokokurai (9)
M9 Ichinojo (10) Ura (11)
M10 Kagayaki (10) Arawashi (13)
M11 Tochinoshin (11) Kotoyuki (14)
M12 Ishiura (12) Tokushoryu (14)
M13 Toyohibiki (14) Onosho (15)
M14 Daishomaru (14) Chiyotairyu (16)
M15 Kaisei (17) Oyanagi (17)
M16 Osunaarashi (18)

I rank-ordered the rikishi by a score based on their rank in the previous basho and their win-loss record. This score, given in parentheses, roughly corresponds to the rank the wrestler “deserves,” (i.e. 3 = M3), though of course the actual rank is affected by the ranks of others and the need to fill all the slots. So for instance, this time around, even though nobody below Mitakeumi had a score above 3, the KW, M1 and M2 slots still needed to be filled.

I then generally simply filled in the ranks from K1W to M16E in this order, with ties broken in favor of higher rank at Haru. The main consistent departure from this order is that those with make-koshi must drop a rank; this affected Takarafuji, Kagayaki, Tochinoshin, Ishiura, and Daishomaru, who otherwise might have been placed a rank or two higher. Takanoiwa, Ura, Arawashi, Kotoyuki, and Onosho benefited by being ranked a bit higher as a result of this rule.

I’ve indicated other deviations from this rank order by italics. I gave the nod to Endo over Okinoumi for M1W given Endo’s popularity and higher rank. I placed Tochiozan at M6 instead of M5 so that Takekaze and Ikioi, who had identical Haru performances at the same rank, would remain at the same rank. And I brought Osunaarashi back to makuuchi in favor of Myogiryu, who drops to Juryo, along with Sadanoumi, Kyokushuho, Nishikigi, and Chiyoo.

Differences in rank from my previous prediction are in color, red for higher and blue for lower; bold indicates differences of more than one step in rank. These predictions are more sensitive to assumptions about how rikishi with identical or very similar scores are ranked relative to each other, and therefore have lower confidence.

Have at it with your own predictions! I might try to compile how we did after the banzuke is released.

Countdown To Banzuke (番付) – Handicapping Demotions


Hokuho Beat Down

Now that we have had a look at the results of Nagoya, we get a clearer picture of who will rise in rank, and who will fall. As mentioned in Countdown To Banzuke (番付) – September Basho, Nagoya was a blood bath in the figurative and literal sense. For every 2 Sumotori with winning records, 3 had losing records, 5 withdrew from injuries, and practically everyone was banged up by the time it all wrapped with Harumafuji winning the cup.

2 Ozeki Kadoban (角番)

A big story to me is that 2 Ozeki are on the bubble for the September Tokyo tournament. While much of the Sumo world focus on if Kisenosato will make Yokozuna and break the Japanese drought, the far more interesting race is for the next Ozeki or two. When an Ozeki has a losing tournament, they are “Kadoban”, or at risk of demotion. When they have 2 losing tournaments in a row, they drop to the lower San-yaku ranks. This could open an Ozeki slot for some of the hard changing Sumotori to climb in rank. On the bubble for Tokyo are

  • Goeido – Could not pull off a win on the final day for kachi-koshi (勝ち越し)
  • Kotoshogiku – Withdrew due to injuries

Noteworthy Predicted Demotions – East

  • Kaisei – Sadly his 7-8 record means he is going to likely drop a rank
  • Kotoyuki – He had an abysmal tournament going 2-13. The Sen-yaku ranks are tough to hang onto, and he will be back to Maegashira, I would think.
  • Mitakeumi – At East Maegashira 1, he had a tough slot to fill. At 5-10 he will be looking to improve in Tokyo.
  • Osunaarashi – The Egyptian was out early with an injury. If he is healthy and is in the Tokyo September Banzuke, it is likely at a much lower Maegashira rank.
  • Toyonoshima – Did not even make it to his first bout, withdrew due to injuries. He is likely back to Juryo ranks for Tokyo

Noteworthy Predicted Demotions – West

  • Tochinoshin – The West Sekiwake is likely to be demoted due to a 6-9 result on Nagoya. He had some great matches, but as stated above, life in the San-yaku ranks is very tough.
  • Ikioi – A fan favorite, he went 5-10 and is likely to be well down the Banzuke, even though he was able to drop and injured Hakuho with a Slippi-toshi.
  • Endo – Dreadful tournament for this guy. 3-12 he was definitely not on top of his game.
  • Aminishiki – Withdrawing before his first bout, he is back to Juryo for Tokyo in all likelihood.
  • Sadanofuji – at 4-11, he is also headed back to Juryo, which sadly is not part of the NHK feed into America. Hope to see him back in the Makuuchi ranks soon.

Next up, we will look at which Rikishi are expected to rise when the Banzuke is published on August 28th

March Tournament: Banzuke


I was right about the Yokozuna and Ozeki. Harumafuji and Kakuryu swapped places and that was the only change from January. However, I thought Ichinojo and Aoiyama would stay in sanyaku. They did not and dropped pretty far. Ichinojo fell to maegashira 1 representing the West while Aoiyama is M3W. Tochiozan fell one spot from komusubi to M1E – opposite Ichinojo.

Terunofuji’s (above) 8-7 record with the special prize did get him sekiwake East. Okinoumi, though, jumped all the way to sekiwake West. The komusubi slots were taken by Tamawashi and Myogiryu; I thought they would get the top maegashira spots.

Kitataiki and Gagamaru were both promoted from juryo, joined by Amuru who gets another chance in the top flight after his 5-10 makuuchi debut in November. As for Ikioi, he did fall to maegashira 13 East opposite Sokokurai. That will be a good opening day bout. Meanwhile Osunaarashi is opposite the geezer, Kyokutenho – another good matchup. Endo fell two ranks, claiming the M5W, while Tochinoshin slipped to M4W. Tokushoryu’s Jun-yusho with 11 wins brings him up to M7W.

Ishiura’s 6-1 record in makushita earned him a promotion to juryo and Shodai’s yusho – with a victory over Ishiura – sees the 23 year old challenged at Makushita 3.

The full banzuke is available at the Sumo Kyokai website.

Or a permanent link from the SumoDB.

Mock Banzuke


OK, if the NFL can have its mock draft, I can have my mock banzuke. The real one comes out in a few hours but, while I wait…

      What we know:

    • Yokozuna & Ozeki mostly unchanged
    • New Sekiwake & Komusubi
    • Tosayutaka demotion
    • Kitataiki & Gagamaru promotion

With Kotoshogiku and Goeido securing kachikoshi, the upper ranks are pretty much set. I expect both of these rikishi to stay representing the West with Giku as W1, and Goeido as W2. I do think that Harumafuji and Kakuryu will swap places as Harumafuji takes W1 and Kakuryu takes E2.

Now, the hard bit. Did Ichinojo and Aoiyama do poorly enough to drop all the way out of the sanyaku and into the maegashira? I do not see either remaining as sekiwake with 9 and 10 losses respectively. Luckily for them, the upper maegashira were pretty well decimated so I expect both to stay at komusubi, though with Ichinojo’s better record, I think he’ll represent the East while Aoiyama will be komusubi for the West.

So, who gets to grab the sekiwake spots? Well, until the last day, I thought Goeido would get one. Now, despite a losing record, I think it’s possible Tochiozan will get one of the slots. Terunofuji was the only one among the top maegashira to get a winning record and with his special prize, I think he might leapfrog into sekiwake. Personally, I don’t think they’ll advance Tochiozan. So, Okinoumi gets the call into sekiwake with his 9-6 record. He had a very strong start to the last tournament but will get rocked during this one. His first week is going to be brutal, facing all yokozuna and ozeki. So, I’m calling Terunofuji as sekiwake for East and Okinoumi as sekiwake for West.

For the top maegashira, Tamawashi will bound to M1E and Myogiryu to M1W.

For the rest, the chips will fall where they may. I look forward to seeing Gagamaru and Kitataiki back among the upper-classmen. My only real question at this point is how far will Ikioi fall? I don’t think he’ll fall into Juryo but he’ll probably be looking up from M13. With this much easier schedule, I expect to see him pull himself together and get kachikoshi. I don’t think he’s going to want 10 or more wins, though, even among these weaker wrestlers. He needs to get some serious skill improvement before he faces the sanyaku again. I always enjoy his bouts and he always seems to go full bore into every match which is more than we seem to get from most maegashira after day 10.

Also, I’m not sure if Kagamio will hang around in the makuuchi. I think he’ll fall to J1E since he had makekoshi and one of his wins came by default.