Aaron Wolf, the 2017 men's 100-kilogram judo world champion, and Shoichiro Mukai both earned gold medals for Japan on Sunday, the final day of the Grand Slam Osaka.
Wolf collected a pair of waza-ari in the final over Canada's Shady El Nahas at Maruzen Intec Arena Osaka. Wolf said he needed to make up for lost time after only managing fifth place at this year's worlds.
"I don't have time to let up," the 22-year-old Wolf said.
Kosei Inoue, coach of the national men's team, said, "That kind of judo, where he mesmerizes an opponent and then goes in for the kill, is back."
Mukai won the men's 90-kg division by defeating the Netherlands' Noel van't End in the final. Japan's Mashu Baker crashed out in the third round.
Japan's Asian Games champion Ruika Sato defeated compatriot Mami Umeki in the women's 78-kg final by ippon, while world champion Shori Hamada finished in third place.
Akira Sone defeated fellow Japanese world champion Sara Asahina in the the women's over-78-kg semifinals only to lose in the final to Cuba's Idalys Ortiz. Asahina and Nami Inamori both walked off with bronze.
The best Japan could do in the men's over-100-kg division was a third place by Kokoro Kageura. Rio de Janiero silver medalist Hisayoshi Harasawa lost in the second round.