Matt Larsen reminds us that martial arts evolve:
As long as the environment forces students to engage in real fights regularly, as in a warlike society, they stay focused on that goal. But in most societies have long periods where they are peaceful. Then things start to change.
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Kano began learning Jiu-Jitsu just a few years after the Satsuma Rebellion. (You may remember the movie The Last Samurai, loosely based on those events in 1877.) Kano was 17 at the time. He opened the Kodokan in 1882 when he was 22 (Stevens, 2013).
Later, as head of what would become Tsukuba University and a top official in Japan’s Ministry of Education, he traveled to Europe and saw how Western education used sports to build character and social unity (Guttmann & Thompson, 2001). Japan at the time didn’t have a direct equivalent to modern organized sport.
So Kano took what he’d learned in Jiu-Jitsu and reformed it into Judo, an art that could be taught safely in schools and used as an educational tool to shape moral character and discipline, not just to win street fights. That purpose shift changed what parts of the art were emphasized in training, and which parts faded.
One clue is in the oldest kata in Judo, Koshiki-no-kata. It preserves the old armored throws from battlefield days, but today is mostly a formality to connect the sport to its combative roots.
Kano’s own writings show he never intended Judo to be only sportive. His original curriculum at the Kodokan included atemi-waza (strikes) and self-defense kata with weapon disarms, the Kime-no-kata preserved techniques against dagger and sword. Students trained these alongside throws and holds.
But after World War II, occupying U.S. forces under General MacArthur banned martial arts training to demilitarize Japan (Guttmann & Thompson, 2001). When Judo returned, it had to present itself as a modern sport to survive. Its Olympic debut in 1964 cemented this path: the competition format rewarded big throws and safe randori, not strikes or weapons work. What survived was what the environment, the schools, the government, the Olympics, rewarded. The striking and weapons elements faded into kata demonstrations, mostly forgotten at the edges of the art (Stevens, 2013).
The most important thing I got from Judo is how to fall. I have never ever once had to use the combat skills.