More than 100 athletes competed in four weight classes, with France, Great Britain, Japan and Germany all well represented.
Japan laid down an ominous marker on the opening day in the Barra Olympic Park, with Chishima Maeda and Joshiro Maruyama each claiming gold.
Maeda, a 19-year-old rising star who won a bronze medal at the 2013 World Cadet Championships in Miami, overcame Brazil's Jessica Pereira of Brazil in the final of the women's under 52 kilogram category.
Chelsie Giles of Great Britain beat another Brazilian, Layana Colman in one of the two bronze medal bouts, while Raquel Silva overcame Helena Kuwabara in an all Brazilian clash for the other place on the podium.
Meanwhile, Maruyama beat Brazilian Lucas Goday in the men's under 66kg final, which saw Great Britain’s Ashley McKenzie and another Brazilian Guilherme Goes claim bronze.
The atmosphere reached its most joyful when home favourite Eduardo Santos ended Japan’s stranglehold over the two-day competition by overcoming Toshimasa Ogata in the final of the under 81 kilograms to clinch the gold medal.
Brazil also claimed both bronze medals courtesy of Igor Pereira and Edu Ramos.
There was more Japanese success in the women's under 63kg division when 2011 world cadet champion Kaho Yonezawa overcame Britain's Bekky Livesey in the final.
Brazilians Jessica Santos and Erika Ferreira each claimed bronzes.
“It was really an excellent event," said IJF head sports director Vladimir Barta. “We can say that we have tested everything, even the public, who were really amazing. We have a nice venue and the staff are really good.”
Larisa Kiss, director of the IJF Presidential office, was equally pleased with the outcome. “It was a really good test event, where the main aspect was the great collaboration between our teams and the amazing atmosphere that prevailed throughout the competition.
“We are pleased with the progress of the organisation, and we are confident the judo event at the Games will be a success.”©Getty Images