Financially stretched trying to pay for his wife's medical care on a teacher's salary, in 1951, Kimura accepted an invitation to travel to Brazil to teach and compete with the increasingly famous Helio Gracie in Brazilian-rules competition. His bout became legendary: after exhausting minutes of scuffling for position and successful throws, Kimura finally downed Gracie and followed up with an attempt to smother him into submission. He saw the opportunity to apply his favorite ude-garami ("kimura") lock. Refusing to surrender, Gracie suffered a broken arm, and Kimura was declared the winner. Paradoxically, the loss made Gracie even more famous.
Kimura's return to Japan was not greeted with acclaim and plaudits, however. Because he had awarded judo promotions without the permission of the Kodokan Headquarters, his promotions were frozen, and he watched as his juniors and inferiors surpassed his 7th dan for the next 40 years. Sadder yet, Kimura entered the shadow world of professional wrestling, largely to make money, where he was betrayed and humiliated.
Despite these setbacks, Kimura's spirit never wavered. He taught judo at his alma mater, Takushoku University, from 1960 until his death in 1993, training Olympic bronze and silver medalists and an All-Japan Champion. Although his rank was frozen at 7th dan from the age of 30 until his death at 75 by the petty vindictiveness of the Kodokan authorities, Kimura never lost his spirit. A life-long smoker, Kimura was diagnosed with lung cancer. Hospitalized after surgery, and in his 70s, Kimura started doing push-ups in his room. He died on April 18, 1993 at the age of 75, arguably the best judo competitor ever-and one of the most important judo figures ever to be mistreated by the leaders of his art.