Day 1 of track and field at the Tokyo Olympics is Friday in Japan, or Thursday night into Friday morning stateside.
The only final of the day is in the men's 10,000m.
Other notable events include: the first rounds of the men's 400m hurdles, women's 100m, women's 800m, men's steeplechase in the earlier session, followed by first rounds of the inaugural mixed 4x400m relay and women's 5000m in the later session, leading up to the men's 10K.
Prelim Round (8pET)
1st Round (11:15pET)
After the event's preliminary round, unique to the 100m for athletes who've yet to achieve the Olympic standard, the women's first-round heats get underway a couple hours later.
Reigning world champion Shelly-Ann Fraser-Pryce of Jamaica, Earth's fastest woman alive, is the favorite and will look to advance to the semifinals. A two-time Olympic gold medalist in the event, having won the 2008 and 2012 titles, Fraser-Pryce clocked 10.63 in June to become the second-fastest woman ever at 100m behind Florence Griffith-Joyner.
Her teammate Elaine Thompson-Herah, the defending Olympic gold medalist, as well as Great Britain's Dina Asher-Smith, Ivorian Marie-Josee Ta Lou and Blessing Okagbare of Nigeria are expected to both advance and later contend for medals.
Absent from the field is American superstar Sha'Carri Richardson, the third-fastest woman in the world this year, who in June tested positive for cannabis-component THC while competing at the U.S. Olympic Track and Field Trials, for which she was handed a one-month suspension and effectively ruled out of the Games.
Men's High Jump
LSU product JuVaughn Harrison, 22, begins his quest to double in both the high jump and long jump, a feat not attempted by an American since Jim Thorpe at the 1912 Stockholm Games. Thorpe didn't make the podium in either event but still won gold in both the pentathlon and decathlon. Harrison has the third-best clearance in the world this year at 2.36m (7 ft, 8 ¾ in).
The event's joint world leaders both within the last month met a mark no one had bested since 2018. Ilya Ivanyuk of the ROC, the 2019 world bronze medalist, jumped 2.37m (7 ft, 9 ¼ in) in May, and it was equaled the next month by Belarusian Maksim Nedaekau.
1st Round (8:30pET)
Defending Olympic champion and two-time reigning world champion Conseslus Kipruot of Kenya did not qualify at his nation's trials and is facing criminal charges and possible prison time.
Another 2016 Rio Games podium finisher missing from the field: American record-holder Evan Jager, who didn't compete at U.S. Olympic Trials due to leg muscle tears.
Moroccan Soufiane El Bakkali, fourth in Rio, was until the Monaco Diamond League the fastest man in the world this year. He won silver and bronze at the 2017 and 2019 World Championships, respectively. One of the two steeplers to best his time in Monaco, 2019 world silver medalist Lamecha Girma, didn't race at Ethiopian Trials but was still added to the team.
The other is Abraham Kibiwot, a member of Kenya's rookie trio contingent looking to keep their nation's streak alive of nine straight Olympic golds in the event.
1st Round (9:25pET)
With the entire podium from the 2016 Rio Games missing, the United States is in great position to end its longest women's medal drought on the track and, perhaps, has an outside chance at a sweep.
Due to a 2018 rule change regulating blood testosterone levels permissible in athletes competing in women's races from the 400m to the mile, two-time reigning Olympic 800m champion Caster Semenya of South Africa, 2016 silver medalist Francine Niyonsaba of Burundi and bronze medalist Margaret Wambui of Kenya are all unable to compete in the event.
The U.S. last won women's 800m gold 53 years ago when Madeline Manning took first at the 1968 Mexico City Games.
Their Tokyo team is as strong as it has ever been led by 19-year-old prodigy Athing Mu, the world leader and winner at U.S. Olympic Trials, at which she made her professional debut. She's joined by 2019 world silver medalist Raevyn Rogers and American record-holder Ajee Wilson, the 2019 world bronze medalist.
Men's 400m Hurdles
1st Round (10:25pET)
Arguably the best track and field event Tokyo has to offer, the men's 400m hurdles at the postponed 2020 Olympics is almost certain to go down as one of the greatest competitions in the sport's history.
In June 2018, Qatar's Abderrahman Samba became the first and only hurdler since then world record-holder Kevin Young to go sub-47 seconds. About a year later he was joined in the exclusive club by both two-time reigning world champion Karsten Warholm of Norway, and American Rai Benjamin, who accomplished the feat together at that year's Zurich Diamond League meet, part of the Weltklasse Zurich.
Later on at the 2019 World Championships, Warholm, Benjamin and Samba went a respective 1-2-3.
Things heated up even more last month when Benjamin took a crack at Young's world record at the U.S. Olympic Trials, coming within .05 of the mark to pass Warholm and become the No. 2 all-time.
But just five days later, the Norwegian actually took the record down at a Diamond League meet in Oslo, clocking 46.70 to break Young's 29-year-old time set at the 1992 Barcelona Games.
1st Round (6aET)
Kenyan Hellen Obiri enters as the two-time reigning world champion with a silver from the 2016 Rio Games. She, like many of her competitors, plans to double in this event and the 10,000m.
One of the others is Sifan Hassan of the Netherlands, the reigning world champion in both the 1500m and 10,000m. The Ethiopian-born world record-holder in the mile is actually attempting a historic distance triple, also set to compete in the 1500m.
Ethiopia's Gudaf Tsegay is the world leader, having clocked 14:13.32 in June. The 2019 world 1500m bronze medalist ran the 800m in Rio and set the 1500m indoor world record in February.
Women's Triple Jump
The women's triple jump is on world-record watch as two-time reigning world champion Yulimar Rojas of Venezuela, the 2016 Rio Games silver medalist, attempts to take down Ukrainian Inessa Kravets' 26-year-old mark of 15.50m (50 ft, 10 ¼ in) from 1995. The already world record-holder indoors has the top nine jumps of this Olympic cycle.
Defending Olympic champion Caterine Ibarguen of Colombia aims to make her third straight podium, while American record-holder Keturah Orji tries to win her first Games medal after a fourth-place finish in Rio. She posted a personal-best 14.92m (48 ft, 11 ½ in) in April.
Women's Shot Put
Two-time reigning world champion and world-leader Gong Lijiao of China, despite having two Olympic medals, has never stood atop the Games podium — she took fifth at her home nation's 2008 Beijing Games, but nearly a decade later was elevated to fourth, then bronze, after the Belarusian silver and bronze medalists were disqualified in 2016 and 2017; in the meantime, she took fourth at the 2016 Rio Games and shortly thereafter was upgraded to silver after the disqualifications of the gold and bronze medalists.
American Michelle Carter, the defending Olympic champion, is absent from the field. She had surgery in June to remove a tumor from her right ankle, later revealed to be benign.
Two of her fellow countrywomen are positioned to contend for medals: Jessica Ramsey, who threw a personal-best 20.12m at U.S. Olympic Trials, and Raven Saunders, fifth in Rio.
Mixed 4x400m Relay
1st Round (7aET)
Making its Olympic debut in Tokyo, the mixed 4x400m relay features each team fielding two men and two women in the order of their choosing. When it made its world-championship debut in 2019, most countries went with a male-female-female-male sequence.
American Allyson Felix ran the United States' second leg in Doha to win her 12th world title and is poised to compete in the event in Tokyo. If she were to secure a medal it would be her 10th at the Games, tying Carl Lewis for most Olympic track and field medals by an American and break her tie with Jamaica's Merlene Ottey for most Olympic track and field medals by a woman.
Uganda's Joshua Cheptegei, the world record-holder in both the 5000m and 10,000m, plans to double in the two.
Sixth at the 2016 Rio Games, Cheptegei broke the 5K mark last August and then, less than two months later, the 10K record, besting Ethiopian Kenenisa Bekele's times in both events.
The 24-year-old phenom is attempting to earn Uganda its first Olympic medal in the event, as well as the 5K.
Great Britain icon Mo Farah, winner of the last two Olympic titles, tried but was unable to qualify at his team's trials.