The ¥56.7 billion (£349 million/$434 million/€398 million) Centre, located in the Kōtō ward in eastern Tokyo, was the scene of some of the most memorable moments of the Olympics, including American Caeleb Dressel's 50 and 100 metres freestyle double, Australia's women winning eight of the 17 gold medals available in the pool and the United States' Katie Ledecky winning the 800m and 1500m, her seventh and eighth titles at the Games.

Home fans, meanwhile, will always remember the venue for Yui Ohashi winning the women's 200m and 400m individual medley. 

The plan is now for the reconfigured Centre, which held 12,000 spectators during the Olympics and Paralympics, to host more major events in the future.

"As a new sacred place for swimming, we will hold many high-level international and national competitions here," Koike promised.

"We hope that the best athletes in the world will come together, that many world records will be created and that we will see a range of emotions."

Early winners in the Japan Swim event, a qualifying meeting for this year's World Aquatics Championships in Fukuoka, included Rikako Ikee. 

She won the 100m butterfly in 57.68sec.

It her fastest time since returning to the sport after her leukaemia diagnosis in 2020.

Ikee's time ranks her eighth in the world this year.

"I was able to race having reminded myself that when I’m at my best, I don’t lose to anyone," Ikee said.

Before her illness, she had competed at the 2016 Olympics in Rio de Janeiro as a 16 year old and won six gold medals at the 2018 Asian Games in Jakarta Palembang.

"I know I don’t stand a chance against the world right now, but this is a huge step for me in getting there, I want to really pick it up from here."