Mutually beneficial
The link-up works both ways.
China's swimming megastar Sun Yang, who has pocketed three individual golds so far in Indonesia, fine-tuned his preparations for the Games at the Hong Kong Sports Institute because the climate in the region is similar to Jakarta's.
"I'm very familiar with the institute. I've been here many times," Sun said during his 20-day stay.
"This is a real lucky place for me. I have been here for training ahead of many important international events. I'm familiar with the environment and facilities here.
"All the people here - from management to the security guards - are all very kind."
Back in the 1980s, the mainland benefited from the generosity of Hong Kong tycoon Henry Fok, who donated about HK$100 million (currently $13 million) to build a swimming venue in Beijing after China won the right to host the 1990 Asian Games. The facility was later used during the 2008 Olympics.
Fast-forwarding to the current Asiad, four of Chinese Taipei's basketball team earn their living in the mainland's CBA, including the league's 2017 overall No 1 draft pick, Ray Chen.
It's just another of the myriad of reasons why all four delegations will strive to continue to nurture and encourage such cooperation.