Their national teams might be about to battle for a place at the 2018 World Cup but the elite domestic football competitions of Australia and Japan have reached an agreement to share "technical, marketing and administrative expertise". 
The memorandum of understanding is the first of its kind between the A-League and a foreign competition and is expected to drive co-operation between the competitions, two of the strongest in east Asia.
A delegation from the J-League arrived over the weekend to finalise the agreement with Football Federation Australia and also took in Sunday's grand final in Adelaide.
"This deal brings two of Asia's top football nations closer in a very meaningful way that will not just build relationships, but will have an impact on football development," said FFA chief executive David Gallop. "The J-League and A-League are setting benchmarks in Asia and this is an opportunity to drive each other to even greater heights.
"This aligns with our strategy to drive commercial revenues and audience growth in the A-League and build future generations of successful national teams."
Among the proposals discussed include an increased number of matches between "elite youth" Australian and Japanese clubs and using football as a mechanism improve political, social and economic relations between the nations.
The agreement also aims to address one shared bugbear - the substandard marketing of Asian Champions League matches - by promoting the matches of games from either nation. 
J-League managing director Daisuke Nakanishi said his nation's competition could benefit greatly from linking with the A-League.
"Since last year, we had a number of meetings with Football Federation Australia and found that we have similar environment and visions," said Nakanishi. "Both the J-League and the A-League are still young and developing and we are both aiming to be world class competitions."
Nakanish said that Australia's experience of leveraging ongoing value from the Olympics 16 years ago would be critical for Japan, with other host nations since arguably failing to capitalise on the event's legacy.
"We found some time after the 2000 Sydney Olympics that the sports industry had gradually grown and government policies on sports became very supportive," he said. "We will host the 2020 Olympics in Tokyo and it is our idea to benchmark FFA and the A-League, how they developed since their establishment, especially the cooperation with the government.
"I am so excited to commence this partnership and hopefully one day, two teams from Asia, Australia and Japan will meet in the World Cup final."
The J-League delegation flew to Melbourne after the grand final and will take in the Asian Champions League encounter between Melbourne Victory and Gamba Osaka before visiting the Japanese Embassy in Canberra and the Department of Sport and the Department of Foreign Affairs and Trade.