was a Japanese educator and athlete, the founder of Judo. Judo was the first Japanese martial art to gain widespread international recognition, and the first to become an official Olympic sport. Pedagogical innovations attributed to Kanō include the use of black and white belts, and the introduction of dan ranking to show the relative ranking among members of a martial art style. Well-known mottoes attributed to Kanō include "Maximum Efficiency with Minimum Effort" （精力善用 Sei-ryoku Zen-you）and "Mutual Welfare and Benefit"（自他共栄 Ji-ta Kyou-ei）.