What do Takakeisho, Tochinoshin and Mitakeumi have in common, apart from recently becoming first-time winners of the Emperor's Cup?

The answer, of course, is that all three joined professional sumo after success in the amateur ranks.

The first two won medals at the Junior World Championships, with Takakeisho taking openweight gold in 2014, and Tochinoshin being part of a famous 2004 podium with future rikishi Goeido, Kaisei and Masuto.

Mitakeumi for his part had so much success at the collegiate level in Japan (as a senior he was both university and amateur yokozuna) that the Nagano native earned the right to start his pro career at the rank of makushita ten.

While ōzumō (professional sumo) is a lifestyle, and amateur sumo is purely a sport, both codes have a lot of overlap and the latter is one of the main recruiting grounds for the former.

Inside the ring there are few differences apart from certain techniques banned in the amateur game for safety reasons such as harite — roundhouse slaps to the head.

The minimum age at which one can become a rikishi is 15, but there are amateur competitions for kids as young as three and four. Women can also compete in amateur sumo but are famously barred from even setting foot on professional rings. The first few world championships were held at the Ryogoku Kokugikan in Tokyo, but that venue was no longer available once a women's tournament was introduced.

The amateur with the most success in ozumo to date is Wajima. A two-time national champion, the former Nihon University man went on to earn promotion to yokozuna and lift the Emperor's Cup 14 times.

While professional sumo in recent times has been dominated by Mongolian and Japanese wrestlers, Russia is the preeminent power in the amateur game.