I like sumo. A lot. I follow the tournaments online, watching matches on YouTube a few hours after they’ve aired, then reading commentary on fan sites in English and Spanish. I have, one or twice, participated in virtual sumo leagues, performing dismally as there’s not always much overlap between the style of sumo I love (focused on agility and throwing techniques) and the style of sumo that wins. I show sumo matches to friends, hoping to turn them into fans, and I’ve been known to give talks at academic conferences on the globalization of this very Japanese sport.

But I’ve seen very little sumo in person. This past week was only my second trip to Japan, and while I was privileged to attend a day’s bouts in Ryuguko Kokugikan, Tokyo’s temple of sumo, I sat in the nosebleed seats, peering through the telephoto lens on my camera to follow the action.

I have a very different perspective on the sport after an incredible experience yesterday morning. On Monday, I gave a talk at Tokyo Midtown Hall, organized by Japan’s most prestigious newspaper, Asahi Shimbun, and by Dentsu, Japan’s leading marketing and communications firm. My friend Mr. Mori and his colleagues at Dentsu organized a morning visit to the Oguruma Beya, the dormitory and training academy where a dozen sumo rikishi live and practice.

We arrived in an unremarkable residential neighborhood before 9am. Without the help of Mr. Kitoh, who used to work with the Japan Sumo Association in his role with Dentsu sports marketing, I would have walked past the building unaware of what was taking place inside. We entered, removed our shoes, and walked a few steps before we entered the room that houses the dohyo, the dirt-covered arena where rikishi compete. The dohyo occupied most of the room – a narrow wooden shelf on two sides of the room held half a dozen cushions, where we sat to watch the practice.

The oyakata, the former Ozeki Kotokaze, sat in a leather recliner in the far corner of the room, watching his trainees intently, but largely without comment. As we entered, the rikishi were sparring, fighting bout after bout, with the winner remaining to fight a new challenger. The athletes practicing compete in sumo’s lower ranks; I caught a glimpse of Takekaze and Yoshikaze, the stable’s two top division fighters, in kimonos, heading out into the street.

That the fighters we saw train were not the top guys didn’t diminish the intensity of the practice. Bouts took place every minute or so, lasting ten to thirty seconds, and the winning fighter rarely took a break beyond wiping his face with a towel before facing his next challenge. Other rikishi stretched and practiced charging forward and background on the edges of the dohyo as matches took place in the center.

A sumo tournament features a few dozen bouts, spread out over a long afternoon. Because sumo is as much religious ritual as athletic contest, there are several minutes of preparation before each bout, which often takes as little as five seconds. We likely saw as many matches in an hour of practice as we’d see in two days of tournament sumo. The dominant sound in the room was men panting for breath, as they recovered from one match and prepared for the next. Matches began with no fanfare, no long stare-downs – both rikishi dropped their fists, exploded into one another with a fleshy smack and quickly fought to conclusion. The few matches where one fighter had clearly underperformed were quickly reset and repeated. After an especially good match, a more senior rikishi would huddle with the loser offering advice on what had gone wrong.

Many of Oguruma’s rikishi are massive, with one weighing in above 200kg, which is heavy even by sumo’s standards. I was fascinated by two of the men working out. One was a teenager, built like a rugby player, strong but lanky and lean, without the massive belly and thighs typical of most rikishi. When I praised his performance after the practice, the oyakata told us that he was only 103kg, and had trained for only one year. Given his ability to beat three or four much larger men in a row, it’s easy to imagine him becoming a serious competitor if he’s able to add 30kg to his frame. Another impressive competitor defeated virtually everyone he faced, rarely being forced into shoving matches by larger men by making good use of turning and pivoting, gripping the other man’s muwashi (belt) and spinning him outside of the ring. I was gratified that my friend Mr. Mori, a sumo fan, agreed that these were the two to watch, more impressive than the more mammoth men they moved around the ring.

With a command from the oyakata, the rikishi began a drill I remember from American football practice – moving a blocking sled. In this case, the sled is another wrestler, who slides across the dohyo on a firmly planted foot thrust behind the body. After four passes, the “sled” gently taps his partner on the back, “knocking” him to the ground into a smoothly executed breakfall.

My friend, Ms. Ohnishi, gasped the first time she saw one of these huge men fall so elegantly. My gasp came when all the wrestlers executed full splits, then lowered themselves into push-up position. From years in the martial arts, I know how few people are able to execute a full split, and I’m used to seeing only the most slender and lithe execute the feat. I’ve insisted for years that rikishi are remarkable athletes, but until I saw a 400 pound man execute a flawless split did I understand quite what a blend of strength, flexibility and power the sport requires.

We spoke briefly with the oyakata afterwards, who gave us some insight into the physical strains of sumo. He was the tallest Japanese man I encountered on my trip, standing about six feet tall, still powerfully built in his 60s. He explained that he had recently had back surgery, and had been ordered by his doctor to lose 30kg, the vestiges of his fighting weight. His recliner wasn’t a mark of luxury or power, just a concession to the injuries sumo had done to his body.

I’m a large man, just under the mass of some of the lightest sumo wrestlers. (There’s one remarkably brave Czech, Takanoyama, who fights at 100kg, way lighter than I am.) I guess I’d assumed that sumo wrestlers were similar to football’s offensive linemen, who are massive and broad men, sometimes with a layer of fat covering powerful frames. But the sumo body is different – these guys are small, muscular guys who’ve added 100kg to their frames through a strict dietary regimen. Most return to a normal weight that’s half of their fighting weight. Until watching a young man who hadn’t yet gained his fighting mass work out, I hadn’t understood that sumo is, in effect, a form of extreme body modification.

After exchanging gifts with the oyakata, I left the dohyo with Ms. Ohnishi, who was having a hard time getting her head around the handsome young man who was training to become a rikishi. “He could have a girlfriend, he’s a good looking guy. Why does he want to get so fat?” She noted that sumo was a popular choice for large boys in post-war Japan, as there wasn’t a lot of food to go around, and at least at a Beya, you were guaranteed to get enough to eat.

My younger Japanese friends are always baffled that I’m fascinated by sumo – it’s something their grandfathers watched, not something they pay attention to. My older Japanese friends tend to assume that it’s part of a respectful attitude towards Japanese culture, and then are surprised that I’m knowledgeable about sumo and ignorant of much of what’s rich and engaging about that endlessly fascinating nation. For me, the beauty of sumo is that it’s so simple – two big men pushing each other around – and so complicated, in terms of techniques, of bodies and of global economics.

I am incredibly grateful to my friends at Dentsu, particularly Mr. Mori, for making this visit possible and for the generous hospitality of oyakata Nakayama Koichi.

A full set of photos and videos of my visit is here.