Sumo wrestling has deep ties to Japan and is the country’s national sport. It originated in ancient times to perform and entertain the Shinto deities. The tradition of Shinto priests purifying the ring is still practiced today, but women are not allowed into the ring. The rule came from Shinto and Buddhist beliefs that women had impurities.
An unfortunate injury at a sumo wrestling tournament in Japan brought up tensions between tradition and gender equality.
In 2018, 66-year-old mayor of Maizuru city, Ryozo Tatami, suddenly collapsed during a speech while inside of the ring. Many of the female nurses from the crowd rushed to the ring to provide emergency treatment but were immediately called off the ring by the sumo judge that day. The judge’s actions drew backlash from television commentators and Japanese social media.
Due to the controversy, Nobuyoshi Hokutoumi, the chairman of the Japan Sumo Association (JSA) and a former grand champion, apologized on the behalf of the judge and expressed gratitude for the women who rushed to help. 
The mayor suffered from a subarachnoid hemorrhage, a life-threatening brain bleed, but was fortunately stabilized in a hospital.
Sources: https://www.theguardian.com/world/2018/apr/05/women-ordered-off-stage-at-sumo-contest-after-trying-to-help-stricken-mayor
https://www.japan-guide.com/e/e2080.html
