https://en.wikipedia.org/wiki/Dohy%C5%8D
https://www.japantimes.co.jp/sports/2018/09/09/sumo/sumo-101-ring/
https://moshimoshimo.wordpress.com/2014/07/18/dohyo-matsuri-a-ceremony-of-a-sumo-tornament-sumo-is-still-a-shinto-ritual/
https://www.kokugakuin.ac.jp/en/article/50375
Watch here
https://www.youtube.com/watch?v=1wHi9fSECqw
https://www.youtube.com/watch?v=3C9kCScVr5k
News:
https://www.nikkansports.com/battle/sumo/news/202006270000579.html
https://www.theguardian.com/world/2020/jun/26/sumos-heaviest-ever-wrestler-urges-others-to-keep-eating-habits-in-check
COVID:
https://english.kyodonews.net/news/2020/05/3e7e903404a5-focus-sumo-world-floored-by-axed-feature-wrestlers-death.html
https://www.japantimes.co.jp/sports/2020/06/10/sumo/virus-will-force-sumo-fans-wrestlers-adjust-new-normal/
https://english.kyodonews.net/news/2020/05/ad252ad573f1-sumo-jsa-begins-coronavirus-testing-for-wrestlers-stablemasters.html
https://slate.com/culture/2020/04/sumo-wrestling-coronavirus-japan.html