They had been included on the programme in Tokyo in response to the International Olympic Committee (IOC) President Thomas Bach’s Agenda 2020. This had called for "regular reviews of the programme to be based on events rather than sports".

Originally, the Olympic Charter had simply required that sports be "widely practised" across a designated number of countries and continents.

Later guidelines took into account factors such as gender equity, compliance with doping statutes and also crowds attracted, television viewing figures and modifications made to ensure the sport remains attractive to television audiences.

Agenda 2020 modifications also made it possible for "Organising Committees to make a proposal for the inclusion of one or more additional events for that edition of the Olympic Games."

The four thus selected were introduced alongside baseball-softball which enjoys a wide following in the host nation and returned after missing London 2012 and Rio 2016.

The new regulations have certainly meant that the race for inclusion in the Games has become more competitive than ever, a trend likely to be continued over the next two years as potential sports jockey for position at Los Angeles 2028.

The popularity of skateboarding in Japan would have made certain that in normal times, the Ariake Urban Sports Park would have been one of the hottest tickets.

As a result of measures to prevent the spread of COVID-19, events were played out without paying spectators. Even so, skateboarding exceeded the fondest expectations of the organisers. Blessed by scorching temperatures under cloudless skies, it played out over four days of competition and looked spectacular on television.

At the closing of every Olympic Games, the IOC President makes the time honoured declaration, "I call upon the youth of the world to join us in four years from now."

It had particular relevance for skateboarding.

Twenty-one-year-old Yuto Horigome, gold medallist in the men’s street competition, was the oldest winner. He seemed positively ancient by comparison with the medallists in the women’s competitions.

Gold medallist Momiji Nishiya was only 13 years and 330 days old when she became Japan’s youngest Olympic champion by winning women’s street.

When the inclusion of skateboarding was originally ratified at the 2016 IOC session in Rio de Janeiro, Brazilian Rayssa Leal was only eight years old. When she won silver a few weeks ago in Tokyo, she was still only 13. 

She arrived home in Sao Paulo to a phalanx of photographers at the airport. Leal was soon to discover a freshly-painted mural in her honour at her school and enthusiasts reported a spike in recruitment for the sport, simply because of what they had seen at the Olympics.

Japanese bronze medallist Funa Nakayama is only 16.

It was a similar story in the women’s park event.

Sakura Yosozumi, 19, took gold but her Japanese compatriot Kokona Hiraki had yet to celebrate her 13th birthday. Britain’s Sky Brown had only just turned 13 and place third, behind Hiraki.

In the men’s park preliminary competition, Australian Kieran Woolley careered into a cameraman and then came back to exchange a fist bump. Very soon, the moment went viral, trending on social media.

His 18-year-old compatriot Keegan Palmer won gold after producing a superb run, while 26-year-old silver medallist Pedro Barros of Brazil soon emerged as an articulate spokesman for the sport.

"We were seen as kids by people a couple of years ago. Now we are making history," Barros said.

"Skateboarding is a lifestyle it goes way beyond just a sport. It is beautiful we are able to be here in the greatest sporting event in the world. I am sure that the message that I’ve always wanted to send across with the skateboard family has reached its target, the message of respect, that we can fall down but that we can rise up again and continue fighting. The Games show that people from different countries are all one."

Time Magazine described how the athletes "managed to fill the mostly empty skatepark with joy as hip-hop thumped in the background. The skaters were generous with hugs and applause after impressive runs."

When the medallists in skateboarding arrived to meet the media, they walked in through an avenue of applauding volunteers. The subsequent conferences did in some ways feel like an evangelist meeting.

The cynical might say the skaters had been coached to be on-message, but they also demonstrated genuine unforced delight that they were part of the Olympics.

The Associated Press described it as a "tropical fairytale".

Surfing will also keep its place in three years from now although at Paris 2024, it competition actually take place at Teahupo'o in Tahiti.

"Tokyo 2020 was without a doubt a resounding success," claimed International Surfing Association President Fernando Aguerre after competition came to an end at Tsurigasaki Beach.

"We even finished the day with a beautiful rainbow. The future of Olympic surfing is looking bright with inclusion in Paris 2024, and then two clear opportunities for surfing in LA 2028 and Brisbane 2032. This is a great start to surfing’s Olympic journey."

Aguerre had sported a Hawaiian shirt and straw hat for a photograph with IOC President Bach.

"I hope that the audience watching could feel the power of surfing, the connection with nature, and the youthful energy that we brought to the Olympics. I hope that the stoke and joy of our sport resonates around the world and shows people how sport can be used to make positive social change. Additionally, as daily users of our oceans, it’s my hope that the rest of the world can join us in taking better care of them," Aguerre said.

"Seeing the first Olympians step atop a podium with medals around their neck brought tears to my eyes. This moment was one big step. Olympic surfing has exposed a whole new generation of youth to the sport. Children watching this moment from all around the globe now know about surfing and have their own dreams to pursue. They know that becoming an Olympic surfer is a goal that is possible to achieve."

Women’s champion Carissa Moore, a native of Hawaii, invoked the spirit of an illustrious Olympic swimming champion from a century ago, Duke Kahanamoku who had advocated the inclusion of surfing even then.

When she returned home, she draped a leis, a traditional Polynesian island garland, around Kahanamoku’s statue.

Such was the impact of the sport’s Olympic entry that at a new exhibition in Waikiki, artist Eduardo Bolioli depicted Moore and Kahanamoku as part of a display of five surfboards in the Olympic colours.

Hawaii governor David Ige also declared August 5 to be "Carissa Moore Day" in the islands.

Brazil’s Italo Ferreira won gold in the men’s event to become the first Olympic champion in the sport.

"I truly believe that the Olympics will change our lives," Ferreira said.

"Not just the medalists, but for all the surfers that competed in this historic event." The Brazilian also claimed "every surfer has a piece of this gold medal".

Many in the Spanish press were surprised by the success of 18-year-old Alberto Ginés López in sport climbing.

"I didn't expect it at all. I didn't expect to get into the final. A dream come true," Ginés López said after winning men's gold.

"Our goal from the start was to get into the final, we knew it would be difficult, and then we were in the final. A few things hadn't gone to plan, and we just knew we had to do the best we can." 

Ginés López is from the Extremadura region. Literally translated from Spanish, this means extremely hard.

It was an apt description of the difficulties Ginés López had faced in training, not least because of the lack of facilities in his home region.

"It is as if a skier emerged from the Sahara," his coach David Macia suggested.

The willingness of the climbers to exchange information with their competitors was seen by many as emblematic of the Olympic spirit.

"This was the image of the day", declared Spanish newspaper El Mundo.

Five different countries appeared on the podium, with Slovenia’s Janja Garnbret taking the women’s title.

"We have been overwhelmed by the great support and interest in our sport that we have received here in Tokyo and across the globe," International Sport Climbing Federation President Marco Scolaris said.

"Our climbers, the ambassadors of our sport, are really enjoying their first Olympic experience."

Karate is the only sport of the new quartet which faces an as yet uncertain Olympic future.

A martial art with origins in the 17th century, it had been waiting a long time for Olympic acceptance. Back in 1981, karate was included on the programme of the first World Games in Santa Clara. Also part of the programme that year was taekwondo, which earned Olympic recognition 21 years ago at Sydney 2000.

Karate has not been included on the roster for Paris 2024, yet officials remain optimistic about its Olympic future.

"We have shown to the world that karate is a unique sport," World Karate Federation President Antonio Espinós insisted.

"We have shown the merits to be in the Olympic programme as a permanent sport. Karate is a sport that needs very special athletic preparation and very special technique. This is something we can offer to the Olympic Movement because it corresponds to the Olympic values.

“We are in the best situation to continue in the Olympic Games. We will improve as a sport better and faster inside the Olympic Movement than outside of it. After our success in Tokyo, the IOC should show solidarity to consider Karate as a permanent Olympic sport."

More than 116 French Parliamentarians have signed a letter calling for the sport to be added to the Paris 2024 programme, with Olympic champion Steven Da Costa and the French Karate Federation also petitioning for a reprieve, but the Organising Committee has so far insisted the sport programme cannot be changed.

At Tokyo 2020, over the course of three days, competitors from 36 nations and one from the Refugee Olympic Team took part and medals went to 20 countries. A different nation won every event. These included men’s and women’s kata, a classical form of the sport in which the participants attempt to demonstrate the perfect form in offensive and defensive moves. The more familiar head-to-head kumite bouts used video referrals. The officials in the sport will surely examine ways in which they can engage wider Olympic audiences viewing karate for the first time.

Karate was staged in the impressive Nippon Budokan, the same arena which had hosted judo over the previous week. Devotees might draw some comfort from the experiences of judo in the 1960s.

It made its Olympic bow at the Tokyo Games of 1964, but it was originally envisaged that this would only be a one-off. A vote taken at the 1963 Session in Baden Baden had decided that there would be no judo at the 1968 Mexico Games.

When the IOC met in Tokyo in 1964, future FIFA President João Havelange was amongst those who called for its continued inclusion in the Games.

"Judo is the greatest combat sport," Havelange told fellow IOC members. He said that "the decision not to include judo in 1968 caused considerable moral and material prejudice to a modern sport and immense distress to our Japanese friends."

Despite this intervention by Havelange and a later plea made by International Judo Federation President Charles Palmer, judo was not included on the programme for 1968. It was eventually reinstated in time for the Munich Games in 1972. Judo has remained as part of the programme ever since.

Volleyball, another sport which made its Olympic bow at Tokyo 1964, has been included in every Olympic Games since that time.