Judo (meaning "gentle way") was created as a physical, mental and moral pedagogy in Japan, in 1882, by Kanō Jigorō. It is generally categorized as a modern martial art which later evolved into a combat and Olympic sport. Its most prominent feature is its competitive element, where the objective is to either throw or takedown an opponent to the ground, immobilize or otherwise subdue an opponent with a pin, or force an opponent to submit with a joint lock or a choke. Strikes and thrusts by hands and feet as well as weapons defenses are a part of judo, but only in pre-arranged forms (kata) and are not allowed in judo competition or free practice (randori). A judo practitioner is called a judoka. The philosophy and subsequent pedagogy developed for judo became the model for other modern Japanese martial arts that developed from koryū (traditional schools). The worldwide spread of judo has led to the development of a number of offshoots such as Sambo and Brazilian jiu-jitsu. Judo is a hierarchical art, where seniority of judoka is designated by what is known as the kyū -dan ranking system. This system was developed by Jigoro Kano and was based on the ranking system in the board game Go,Beginning students progress through kyu grades towards dan grades.
A judoka's position within the kyu-dan ranking system is displayed by the color of their belt. Beginning students typically wear a white belt, progressing through descending kyu ranks until they are deemed to have achieved a level of competence sufficient to be a dan grade, at which point they wear the kuro obi (black belt). The kyu-dan ranking system has since been widely adopted by modern martial arts. The highest grade ever awarded jūdan (tenth degree black belt) has no formal requirements and is decided by the president of the Kodokan, currently Kano Jigoro's grandson Yukimitsu Kano. As of 2011, fifteen Japanese men have been promoted to this rank by the Kodokan, three of whom are still alive; the IJF and Western and Asian national federations have promoted another eleven who are not recognized (at that level of rank) by the Kodokan. On July 28, 2011, the promotion board of USA Judo awarded Keiko Fukuda the rank of 10th dan, who was the first woman to be promoted to judo's highest level, albeit not a Kodokan-recognized rank.