Judo was first introduced to the Summer Games in Tokyo in 1964, with an obvious nod to the host country, Japan. But judo was already an established international phenomenon by that time, across America and Europe.
According to the Family Weekly article, “few sports are growing as swiftly in America today as judo. At the close of WWII, there were perhaps 10 judo clubs in the US and no more than 100 wearers of the black belt. Now there are at least 1,200 clubs, more than 2,000 black belts, and 300,000 people participating in the sport.”