Doreen Simmons, a British-born teacher of Latin and Greek who settled in Japan in the 1970s and became a renowned authority on sumo wrestling and an English-language commentator on Japanese television, died April 23 in Tokyo. She was 85.

Her death was announced by the organization For Empowering Women in Japan. The cause could not be learned.

Ms. Simmons taught in England and Singapore before moving to Japan in 1973 to work as an English teacher. From the beginning, she was drawn to the ritual qualities of sumo wrestling, the Japanese national sport with a history dating back 1,500 years.

She learned the Japanese language and later became an editor of English-language press releases and documents for Japan’s foreign ministry and other branches of the government.

All the while, Ms. Simmons deepened her devotion to sumo, in which two enormous men in loincloths attempt to push each other to the ground or beyond a prescribed circle. She attended tournaments and became one of the few women allowed in the male preserve of the heya, or stable — the traditional training facilities and living quarters of sumo wrestlers.

She learned that the ritual ceremonies of sumo, such as the tossing of salt in the ring before a bout, are intertwined with ancient Shinto religious rites.

“My first attraction was things like the throwing of salt, which I recognized straight away as a purification,” she told an Australian newspaper in 2007. “I also enjoyed, right from the beginning, the colorful gyoji [referees] and their ritualized calls and poses, and the calm Buddha-like faces of the men waiting their turn.”

Ms. Simmons moved to Tokyo’s Ryogoku district, the heart of the sumo world, and in the 1980s began to write about the sport for English-language publications in Japan, including Sumo World. She came to be seen as one of the few outsiders with a firm grasp of the sport’s traditions and subtleties.

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She wrote authoritative articles about sumo referees, who are costumed in elaborate silk robes and have almost a priestly role in maintaining order. She wrote about sumo hairdressers, who spend years learning how to use combs and oils to create the wrestlers’ distinctive topknots.

Ms. Simmons also examined the social hierarchy of sumo, in which young wrestlers begin their apprenticeship by working in kitchens, cleaning and caring for the personal needs of more advanced wrestlers. (The sumo world has had several recent scandals, including the hazing-related death of a 17-year-old wrestler in 2007 and later accusations of match-fixing.)

Sumo wrestlers consume huge quantities of rice and beer to maintain their formidable weight, which often exceeds 400 pounds. Despite their bulk, Ms. Simmons often explained, the wrestlers were superbly trained athletes who possessed remarkable quickness, agility and strength.

“Unless you’ve actually have seen sumo, you have no idea how fast it is,” she told CBS’s “Sunday Morning” in 2009. “They are not lumbering giants at all.”

In 1992, Ms. Simmons began to provide English-language sumo commentary for Japan’s NHK television network.

“At the beginning there were three play-by-play men who had experience of broadcasting games like baseball, but their knowledge of basic sumo was newly acquired and pretty limited,” she told Britain’s Express newspaper in 2017. “They wanted the color provided by commentators like me who were hired because we were already knowledgeable about some aspect of sumo, and had gained our specialist knowledge in our own time and, mostly, at our own expense.”

In her understated British accent, Ms. Simmons described various sumo holds and moves, such as the kainahineri (a two-handed arm twist) or the tsuridashi, when a wrestler grabs an opponent’s mawashi, or belt, and tosses him out of the ring.

Doreen Simmons was born May 29, 1932, in Nottingham, England. Her father served in the British army.

She studied classics and theology at the University of Cambridge, graduating in 1954. She was a teacher of Latin and Greek for several years before moving to Singapore, where she taught at a British army school in the 1960s.

She was reportedly married at least once, but information about survivors could not be confirmed.

Ms. Simmons held a variety of editorial and translation jobs, and continued her work for the Japanese foreign ministry until shortly before her death. She was a well-known presence in Tokyo’s community, attending Anglican church services, acting in plays and musicals, and singing in the British embassy’s choir.

She also learned to play Irish and African drums and called herself “a novelty percussionist” who frequently performed at Irish pubs in Tokyo.

She traveled widely, often while volunteering for Habitat for Humanity. While building houses in Mongolia, she “fell in love with Mongolian tattoos” and celebrated her 71st birthday with her first tattoo.

Last year, Ms. Simmons received the Order of the Rising Sun, one of the Japanese government’s highest honors, for her contributions to the country’s culture.

“The attraction of sumo to the person looking at it for the first time is that you can understand pretty much what is going on,” she told Toronto’s Globe and Mail newspaper in 1997. “But there is so much else that . . . I can honestly say I haven’t stopped learning.”