Organisers of the opening ceremony evoked the spirit of John Lennon and his wife Yoko Ono, 50 years after they wrote the peace anthem Imagine.
A procession of flag bearers from 207 nations was being led by eight children, symbolising that the future is now in their hands.
Olympic chief Thomas Bach began proceedings with the words: “Welcome to the Olympic Games Tokyo 2020! Finally, the moment has arrived.”
He called the global event “a light at the end of this dark tunnel” only made possible because of the Japanese people’s “incredible ability” to overcome adversity.
The ceremony started with four athletes carrying the Japanese flag into the stadium, followed by a person with disabilities and a health worker who cared for victims of the pandemic.
British rower Mohamed Sbihi, 33, and sailor Hannah Mills were making history leading out Team GB — the first time there have been male and female flag-bearers.
As the greatest show on earth got under way, Tokyo 2020 chiefs said they wanted children to be at the forefront of a “peaceful” and “more diverse” fresh start post Covid-19.
They likened it to the future that Beatle Lennon and his Japanese activist wife Ono imagined without “borders, nationalism, warfare, religious constructs or ownership, where life and all its riches are shared in peace and harmony”.
Imagine, co-written by the couple at their Berkshire home, was then being performed in front of a crowd of just 950, with numbers in the stadium restricted to stop the spread of the virus.
US First Lady Jill Biden, Emperor Naruhito and French President Emmanuel Macron were among the VIPs, officials and media guests allowed inside.
Mills, also 33, who will be defending her title in the women’s 470 class, said she was “overwhelmed, honoured and proud” to be a flag-bearer.
She said: “I will carry the flag for Team GB, the athletes and the whole of the UK, for the Olympics and what they represent and for the planet and the changes we need to make.”
Star names competing for Team GB include swimmer Adam Peaty, cyclist Laura Kenny and sprinter Dina Asher-Smith. Even before the opening ceremony started, Team GB was already in action.
Sarah Bettles, from Harold Wood, near Romford, finished 15th of the 64 competitors in the opening ranking round of archery at Yumenoshima.
British rowers also started their campaign with Vicky Thornley making a strong start in the women’s single sculls.
Thornley, the first British female single sculler to gain Olympic selection for 20 years, crossed the line first in her heat nearly three seconds ahead of Switzerland’s Jeannine Gmelin.
British duo Graeme Thomas and John Collins made it through to the semi-finals in the double sculls, finishing second in their heat behind the Dutch.
A series of testing measures have been brought in to stop the Games becoming a “super spreader” event but despite the restrictions, the virus has already hit the Olympics.
Twelve new cases of Covid-19 were reported on Thursday, bringing the total related to Games personnel to 87. There have been eight positive cases among athletes.
Meanwhile, opposition to the IOC’s ban on protests intensified with more than 150 athletes, academics and social justice advocates signing an open letter demanding changes to Rule 50.
Games chiefs earlier this month relaxed the rule to allow athletes to take a knee for racial justice.