Takuya Haneda and Aki Yazawa swept the two canoe/kayak slalom gold medals available on Wednesday at the 2018 Asian Games, as the badminton and swimming athletes also did their bit on a successful day for Japan.

Haneda put down an error-free run in the men's C1 final, paddling his canoe through the white-water course near Jakarta to score 90.06 points, 0.52 ahead of silver medalist Chen Fangjia from China.

"I was able to defend my title and I am relieved," said Haneda, who also won bronze in the event at the 2016 Olympics. "Because my only chance of winning was paddling my kind of race, I kept believing in myself."

(Yazawa (L) and Haneda show off their goald medals)

Yazawa followed her compatriot's lead, but she had an easier time of it in the women's kayak singles final, gapping China's Li Tong by navigating a clean run down the course.

Yazawa's 95.83-point score was 4.34 ahead of the silver medalist and made her the first female Japanese canoe/kayak slalom gold medalist at an Asian Games.

Japan's women were able to defeat their great rival China to claim gold in the badminton team event.

The Japan players found themselves in a one-match hole after world No. 2 Akane Yamaguchi lost the opening rubber, but came roaring back, Yuki Fukushima and Sayaka Hirota winning their doubles to even the tie before Nozomi Okuhara won her singles match and Misaki Matsutomo and Ayaka Takahashi closed out the gold in the final doubles.

The gold was Japan's first in this event in the Asian Games since 1970 and the nation's first badminton gold since 1998.

At the pool, Japan again went swimmingly.

Yasuhiro Koseki put together a heroic race from Lane 1 to win gold in the men's 100-meter breaststroke.

He added the 100 title to the 200 he won earlier in the week, and with the 50 still to come, he is on track for a hat-trick of breaststroke gold.

Daiya Seto upset reigning Olympic champion and countryman Kosuke Hagino to win the men's 400 individual medley with a season's best time, something he said gives him confidence ahead of the Tokyo Olympics.

(Seto (R) outpaces Hagino to win the 400 medley)

Young gun Natsumi Sakai won her second gold of the games in the women's 100 backstroke, the 17-year-old outdueling fellow Japanese Anna Konishi.

The last gold of the night for Japan came from the men's 4x100 freestyle squad, which beat China by half a body-length.

For the first evening at these games, Rikako Ikee had to return to the athletes' village without a gold medal, but she did take silver as part of the mixed medley and became the first Japanese woman to win six medals at a single Asian Games.

The men's fencing team joined the gold rush on Wednesday, winning the team epee 30-22 over China, the first gold in the sport for Japan at these games. The Japanese women chipped in with a medal of their own on Wednesday, a bronze in team sabre.

With Tomohiro Araya winning silver in wushu, Eri Yonamine a bronze in road cycling and Japan's women's gymnastics team a bronze, the country's total medal count after Wednesday's competition sits at 68.

China, with 37 gold is still well in the lead, but Japan's 20 gold, 23 silver and 25 bronze gives it a strong lead over South Korea, which has won 11 gold, and Iran, which had wrestling success on Wednesday and now has seven.

In team sports, Japan's scandal-hit men's basketball team had an 88-82 win over Hong Kong, despite going into battle with eight players, while the reigning women's soccer champion North Korea lost to book a spot against Japan in the quarterfinals.

Japan's men's handball team beat Iraq 27-24 to keep its hopes of reaching the semifinals alive, and the men's hockey team stayed unbeaten with a 3-1 win over Indonesia but has a huge test against India on Friday.

Japan's softball team had another dominant day, beating South Korea 10-0 and China 14-1, and the men's volleyball team scraped a 3-2 win over Kazakhstan to move into second in its group behind its Friday opponent Myanmar.