Judo competition
Judo was a sport at the 2020 Summer Olympics in Tokyo, and featured around 393 judoka (柔道家: judo practitioners) competing in 15 events, seven each for both men and women as well as a new mixed team event. The 2020 Summer Olympics were postponed due to the COVID-19 pandemic, and the judo competitions were held in July 2021 at Nippon Budokan.
The tournament brackets were drawn on 23 July, with the top 8 judoka in each weight class seeded.
Participating nations.
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New rules.
Judo, since the sport's introduction in the 1964 Tokyo Olympics, has changed and evolved over time. There were several rule changes made in the 2020 Summer Olympics.
Based on the 2016 IJF Judo rule changes, the time for men's bouts is four minutes, the same as women's bouts. 
There was also a change in scores of a Waza-Ari, a technique that requires a judoka to pin his/her opponent for 10 to 20 seconds or to throw the opponent successfully but not well-controlled to be awarded as Ippon. 
As basic Judo rules, there are three ways to win: 1) to throw the opponent to the ground in a certain efficiency, 2) to hold down the opponent for 20 seconds, 3) to force the opponent to submission by arm lock or strangulation.
Originally, gaining points of Ippon ended the bout, but now Waza-aris are awarded equal to Ippons. With this rule change, penalty scores no longer end the bout.
In addition, the mixed team competition was added: six individuals in their national team compete against individuals of the same weight category from another national team. A team wins when it has won four rounds. This new content aims to engage in gender equality, as well as a union through sport.
In addition, the mixed team competition was added as a new content of Judo games in the Olympics. Six individuals in their national mixed team compete with individuals of the same weight category from another national team. A team wins when it won at least four rounds of six. This new content aims to engage in gender equality as well as a union through sport. It is considered one of the most gender equal competition in Olympic games France, the next Summer Olympics' host country, became the first team to win a gold medal in this new competition for mixed teams, defeating Japan 4-1. This was considered as a memorable moment for judo in the 2020 Summer Olympics.
Politically motivated withdrawal.
 ;section begin=withdrawals / ;Selected to compete at the 2020 Summer Games in the -73 kg weight class, Algerian judoka Fethi Nourine and his coach Amar Benikhlef announced his withdrawal following the conclusion of the draw of competitors. 
Nourine was quoted as saying his political support for the Palestinian cause made it impossible for him to compete against an Israeli; Tohar Butbul, the #5 seed in the tournament, whom he was drawn to potentially face in the second round (had he won in the first round), was Israeli. 
The International Judo Federation (IJF) announced the immediate suspension of Nourine and his coach on 24 July 2021, pending a further investigation, while the Algerian Olympic Committee revoked their accreditation, and sent Nourine and his coach back home to Algeria. The Federation explained: "According to the IJF rules, in line with the Olympic Charter and especially with rule 50.2 that provides for the protection of the neutrality of sport at the Olympic Games and the neutrality of the Games themselves, which states that 'no kind of demonstration or political, religious or racial propaganda is permitted in any Olympic sites, venues or other areas,' Fethi Nourine and Amar Benikhlef are now suspended and will face a decision by the IJF Disciplinary Commission, as well as disciplinary sanctions by the National Olympic Committee of Algeria back in their country.'" ;section end=withdrawals / ;
References.
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