A judo belt.
Judo was developed from the ancient sport of jujitsu, which was the hand-to-hand combat technique used by Japanese Samurai warriors.
The martial art, which was adapted into its modern format in the 1880s by Jigoro Kano, had been scheduled to appear at the 1940 Olympics before the outbreak of the Second World War.
In the end, the sport had to wait until the 1964 Games to be included on the programme when Japan hosted the Olympics for the first time in Tokyo.
Judo was dropped for the 1968 Games but returned in 1972 in Munich and has been contested ever since, initially only for men.
The first women's event was held at Barcelona 1992 and in its current format there are seven weight categories for both men and women at the Olympics.
A judo bout is normally won by a competitor - known as a judoka - throwing their opponent to the ground, although the sport does also allow submission holds.
Judokas need to demonstrate strength, dexterity and tactical awareness during what can be highly-physical and fast-paced contests.
Bouts last five minutes and take place on a mat, with competitors grappling for control and scoring points for different throws and holds. A contest ends immediately if a judoka is awarded ippon, which is the maximum one-point score.
In the event of a tie after five minutes, the bout is decided during a golden score period, where the first competitor to score a point of any type is declared the winner.
The format for each weight category involves a straight knockout competition, while a repechage system is used to decide the winners of the two bronze medals on offer and includes all judokas who have lost to either of the two finalists.
Unsurprisingly, the sport has traditionally been dominated by Japan at the Olympics, with France and South Korea also winning a number of medals.