Japanese officials were busy over the last two weeks observing operations in and around Asian Games venues in Indonesia to learn lessons that could help in Tokyo's effort to put on a successful Olympics and Paralympics in 2020.

The priorities they focused on during the 16-day games, which run from Aug. 18 to Sunday in Jakarta and Palembang, ranged from finding effective measures to deal with the heat and heavy traffic, to getting the best out of Japanese athletes.

As Japan's record-breaking temperatures and stifling humidity this summer raised concerns about health risks for athletes and spectators during the Olympics in Tokyo, officials and sports bodies treated Indonesia's similar weather conditions as an opportunity to experiment with various heat countermeasures.

The Japan Association of Athletics Federations, which has tracked body temperatures and analyzed sweat from runners, prepared small bags of ice or palm-sized cold packs to help cool athletes during races.

In addition to periodically holding a cold pack in his hand, Hiroto Inoue, who won Japan's first gold in 32 years in the men's marathon at the Asian Games, made holes in his running gear to help cool his body.

With the race beginning at 6 a.m., an hour earlier than the scheduled start time of the marathons at the Tokyo Olympics, the temperature was still around 26 C, but a number of athletes said afterward that they struggled with the summer sun, despite organizers having installed mist showers at various points.

Tadasu Kawano, a coach of the athletics team, said, "Having each runner starting to think out and devise a better method is a big asset. But we still have room for improvement."

Athletes of other outdoor sports, including soccer, hockey and beach volleyball, used ice to prevent "deep body temperatures" from rising to dangerous levels.

Japanese tennis players utilized ice vests during breaks in play, while golfers had their urine tested every day to enable them to optimize their hydration levels.

The JOC has required all sports organizations to report after the 2018 games what kind of steps they took to beat the Indonesian heat.

In cooperation with the Japan Institute of Sports Sciences, JOC officials said they will study the answers and other data collected during the event to advance arrangements for the national team.

Jakarta's notorious traffic congestion also came under the spotlight. The city has a population of over 10 million, more or less equivalent to the Japanese capital. The Tokyo Organizing Committee of the Olympic and Paralympic Games sent a team tasked with investigating and analyzing transportation issues.

The team of about 10 officials was dispatched to look into how Jakarta's public transportation network functioned during the games and whether competitors were able to travel quickly and comfortably from the athletes' village to their respective venues, according to Tokyo 2020 spokesperson Masa Takaya.

(Fireworks at 2018 Asian Games opening event)

In a bid to curb traffic and pollution, the Indonesian capital closed some streets and expanded its policy of allowing cars with only odd- or even-numbered license plates to use certain major roads on alternate days, a tactic employed before, during and after the Beijing Olympics in 2008.

Despite concerns, there were no severe disruptions caused by traffic jams, according to the officials. Indonesia's National Police Chief Tito Karnavian told a press conference on Thursday that the games also saw no significant security problems.

While some officials pointed out security measures were not as tight as in previous mass-participation events, they said Tokyo has much to learn from Indonesia to create a festival-like atmosphere, such as replicating the scores of food stalls and bands that could be seen outside Jakarta's GBK Main Stadium.

Japanese delegation chief Yasuhiro Yamashita used much of his time to visit where Tokyo gold medal hopefuls were competing, saying that he had to keep tabs on their progress toward the summer of 2020.

Yamashita said the games provided a chance for JOC officials to address any obstacles in the way of Japan reaching its stated target of 30 gold medals, almost double its previous highest tally of 16 achieved at the 1964 and 2004 Olympics.

As it was the last opportunity to bring together a huge national team before the Olympics, Kenji Kasahara, JOC sports department director, said nurturing a "sense of solidarity" among Japanese athletes while living together in the same village was of foremost importance.

Noting that there were many who had not experienced "Team Japan," Kasahara said, they were the "newest addition to the family and it was like leaving for a big family trip for the first time."

He said the athletes of sports newly added to the 2020 program, including karate and sports climbing, were like "relatives" but not real members of the national team until the Asian Games.

Although four basketball players were kicked out of the national team a day after the opening of the games for buying sex in an entertainment district in Jakarta, the officials said they believe many athletes had a good experience of representing their country.

And for Ryo Kiyuna, the men's karate kata gold medalist in Jakarta, the experience got him excited for things to come in Tokyo, he said.

"When I was in my room and having meals at the athletes' village, I thought this kind of atmosphere would be close to what I would face two years from now."