Bonus Episode: Namiyama

In our latest statistics project, Jake introduces us to a new hypothetical wrestler: Namiyama. Namiyama technically does not exist, but is going to help us sound more intelligent as we analyze the kimarite patterns of specific wrestlers. Drop us a line with requests or suggestions at 805-613-SUMO (7866) or find us on social media.

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Theme music by David Hall via SoundCloud

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Bonus Episode 20: Intro to Sumo, Take 2

*Not April Fool’s this time, we promise*

So a year and a half in, we thought it was time to re-do our very first episode, a guide for newcomers to the world of sumo. It’s a bit of an info dump in the first half, but we hope it’s something you can use as a resource if you are struggling with the rules or traditions of the sport. If that’s too boring, try skipping to 29:08 where we embarrass some very special guests with a sumo game show! Feel free to leave us a berating voice mail at 805-613-SUMO (7866) or find us on social media (now including Instagram!)

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Theme music by David Hall via SoundCloud

Natsu 2019 Banzuke Review

Ryan and Jake go over the recently released banzuke with a fine tooth comb while comparing it to the banzuke Ryan put together right after the Haru Basho. Ryan gets a little drunk with power, but we are able to power through with a little help from Jake trying to crush his ego. Messages of congratulations to Ryan for his impeccable guessing ability can be sent to 805-613-SUMO (7866)

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Theme music by David Hall via SoundCloud

Bonus Episode 18: Intro to Sumo, Take 2

*Sorry if we got you with this one, this was our 2019 April Fool’s gag. Check out our ACTUAL new intro to sumo episode in May*

We at GSB are a nostalgic bunch, so we thought it would be cool to edit and re-release our first episode, an introduction for newcomers to the world of sumo. Through the magic of editing, we got rid of a few errors we made and we hope you’ll enjoy!

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Music by David Hall via SoundCloud

Bonus Episode 3: Power Rankings

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As a fun little side project this winter, we put together possibly the geekiest thing we’ve done, and that’s including our fantasy sumo league. Using a variant of professional chess’s Elo ratings, we’ve created a power ranking system that we can update day-to-day to help quantify how well wrestlers are doing beyond just their record. Here’s a quick overview of how it works:

chart.JPG

This first picture is a partial selection of our data entry system (for Kyushu 2017 to be precise). The axes are the list of rikishi in makuuchi and the chart shows which day they faced and who won. In Hakuho’s row, you see a ton of green numbers and 1 red, representing a bunch of wins and 1 loss. The number represents the day they fought and the sign (+/-) and color represent who won. With a little bit more programming this will be the only data entry we have to do and the rest will take care of itself.

daily

This second picture is the first few days of our daily output. Within the column for each day you can see the opponent, the opponent’s ranking, the expected win chance, the change in points, and the wrestler’s new rating. For the most nerdy among you, here is our methodology. We started by assigning 1000 as a baseline value for an average wrestler. We arbitrarily assigned a starting rating based on the banzuke rating of every makuuchi rikishi in January 2017, from 1175 for yokozuna down to 825 for maegashira 16. Here are the formulas we used for the calculations:

expected

This is how we calculated the expected win chance. We take the difference between our wrestler’s rating and his opponents’s and then use a constant, S, to calculate an expected win chance between 0 and 1. A lower value of S means the rating difference will have more effect on the expectation. For the first edition of our ratings, we used S = 200.

rating

This formula takes the previous rating for our wrestler and adds a constant, K, times the difference between expectation and reality. The actual outcome is either 0 for a loss or 1 for a win and we compare that to the win chance previously calculated. K is effectively the max point swing. We are using K = 20 for now.

carryover

This last formula is how we regress to the mean between tournaments. We decided that everyone should be corrected 20% closer to our 1000 baseline. This corresponds to C = 0.8. By occasionally bringing everyone closer to our average value, we mitigate the effect of flukes and help nudge each rikishi’s ratings closer to a value that accurately represents their talent.

Here is a link to the full spreadsheet if you are interested. We plan to keep it updated as often as possible during each basho. Our next step is a more accessible way for everyone to follow along live. Let us know what you think or if you have any ideas for improvement!