Rikako Ikee headlined a stellar night in the pool on Monday, winning two of Japan's four gold medals as she became the first athlete to stand on the top step of the podium three times at the 2018 Asian Games.
After the second day of the games in Jakarta and Palembang, China leads the medal table with 15 gold, Japan is in second with eight, 11 silver and 11 bronze, and South Korea follow with five gold.
However, the good news for Japan on the medal front was drowned out by an unfolding sex scandal, with four basketball players sent home after admitting negotiating the services of Jakarta sex workers while in team uniform.
Japan's sports hierarchy will be hoping the focus quickly shifts back to the 18-year-old Ikee, who won gold in the women's 50-meter butterfly and 100 freestyle, adding to her 4x100 freestyle victory from Sunday.
"I am just filled with happiness that I could get gold in the two events as I have targeted," said Ikee.
Former world champion Kanako Watanabe joined the pool party by defending her Asian Games 200 breaststroke title, and Kosuke Hagino and his 4x200 freestyle relay team won Japan's final swimming gold in the night's last race.
Earlier, Hagino lost his 200 individual medley title, settling for silver when China's Wang Shun touched him out. Shogo Takeda and Ryosuke Irie won silver medals and Reona Aoki a bronze.
Japan's first and so-far only non-swimming gold was won in the equestrian team dressage event.
Masanao Takahashi, Shunsuke Terui, Kazuki Sado, Akane Kuroki and their respective mounts took the nation's second ever gold in the event, and first since 1994.
"Really, I am so happy, I can't believe it," Takahashi said. "The Rio Olympics left such a bad taste in my mouth, I am so happy to be able to get these kinds of results. I am grateful to the horse."
Shogo Nonomura won Japan's first gymnastics medal, when he finished second in the men's individual all-around.
The 25-year-old, a member of Japan's silver medal-winning 2014 World Championships team, finished just 0.8 of a point short of China's gold medalist Lin Chaopan's 86.750-point total.
With Kakeru Tanigawa and Kenta Chiba finishing fourth and fifth in the individual all-around, Japan qualified second behind China for the team final to be fought out Wednesday.
In perhaps one of the biggest surprises of the Asian Games, Japan still is without a gold medal in freestyle wrestling, and on Monday there were medals, but only of the minor type.
Yuki Irie was the only athlete to reach a final, where she was defeated 6-2 in the 50-kilogram division by India's Vinesh Vinesh.
"I'm trying my best to be No. 1 in the world," said a disappointed Irie. "In the final I was unable to bring my opponent down and there were times when I was unable to move. She studied me very well."
Haruna Okuno won 53 kg bronze, and Katsuki Sakagami and hot gold medal favorite Risako Kawai did the same in the 57 kg and 62 kg divisions, respectively.
In fencing, Sera Azuma lost her foil semifinal against South Korea's Jeon Hee Sook, the eventual gold medalist and finished with bronze.
Sergio Suzuki also won bronze, in taekwondo's 58 kg division.
Japan's women's badminton team kept rolling, taking down singles world No. 3 Venkata Sindhu Pusarla and her Indian teammates 3-1 in the quarterfinals.
Pusala got India off to a perfect start, beating world No. 2 Akane Yamaguchi in the first singles rubber, but when doubles pair Yuki Fukushima and Sayaka Hirota and singles star Nozomi Okuhara put Japan in front, not even a rare doubles appearance from Pusala could save India as Olympic doubles champions Misaki Matsutomo and Ayaka Takahashi closed out the tie.
"We couldn't imagine playing Sindhu in doubles," Takahashi said. "Experiencing an opponent with that kind of attacking power in our first match is something we can really build on for our next one."
The men's badminton team also advanced, beating South Korea 3-0.
Japan's men's hockey team opened its Asian Games account with an 11-0 first-up defeat of Sri Lanka behind a hat-trick from forward Kazuma Murata and double strikes from Koji Yamasaki and Kenta Tanaka.
The softball squad stayed unbeaten, backing up Sunday's 7-0 defeat of Indonesia with a 3-1 win over Taiwan.
More on the Asian Games:
Asian Games: Japanese basketball players expelled for buying sex