The International Judo Federation (IJF) announced the launch of World Judo Day at the end of 2010. It takes place every year on October 28, the birthday of judo’s founder Jigoro Kano.
World Judo Day aims to promote the values of the sport and its education system to all judo clubs and all judoka, through IJF Member Federations and with the help of modern communication tools.
Each year has its own distinct theme.
"Stronger together" was the theme for the 2020 edition, in a bid to bring the judo community together and hit back against the coronavirus crisis.
Countries celebrated on social media with in-person events not possible due to COVID-19 restrictions.
The IJF acknowledged how difficult the pandemic had been for many, but stressed how it was important for people to communicate in new ways and stay connected even if unable to compete.
"Amid all that has been endured and the great cost incurred by separation, there is still our sport and it’s fundamental centrality of togetherness," the IJF said.
"So, we have found new ways.
"They are not ideal, they are not perfect, but they offer us small steps towards the happiness of togetherness that we crave."
For 2019’s World Judo Day, the IJF encouraged people to “Plant a Tree” as part of environmental-themed events.
In November, it was announced that more than 5,300 trees had been planted in 75 countries.
IJF President Marius Vizer planted a tree at the Abu Dhabi Grand Slam.
"With this operation we will contribute to preserving our environment and that of our children," Vizer said in Abu Dhabi.
"Climate change is something that affects us all, especially the disadvantaged ones.
"Planting a tree takes on a dimension that is both concrete and symbolic.
"By doing so, we are helping to build a healthier environment.
"It is also a strong symbol of unity and peace in the world."
In Japan, the Kodokan Judo Institute planted a tree in Abiko in Chiba, on the former site of Kano's villa.
In 2018, World Judo Day had the theme of friendship.
Three-time world champion and Athens 2004 Olympic gold medallist Ilias Iliadis of Greece led a special World Judo Day masterclass during the break on day two of the Abu Dhabi Grand Slam.
Local children and senior members of the United Arab Emirates national team alike were put through their paces by the legendary judoka who officially retired in 2017.
Iliadis, who won Olympic gold at the age of 17, led a warm up as the world watched live on the IJF Facebook page.
The children’s smiles were beamed around the world in a fun and friendly atmosphere that, it is claimed, beautifully illustrated the 2018 theme.
Greece’s Beijing 2008 Olympic flagbearer squared off against each participant of the masterclass in randori, a term used in Japanese martial arts to describe freestyle practice.
The younger members also politely requested a second contest against their world-renowned coach, who duly obliged.
Iliadis credits judo with shaping his life and making him the man he is today.