Dan (rank) is by far the most recognizable symbol to the general public. The highest dan ranks are sometimes reserved for the founder or leaders of a style and only high-ranking students can be promoted to them. For example, only five living people hold a tenth dan in judo and only about thirty-five worldwide have been promoted to the rank since its inception; of those 10th dan promotions only fifteen were conferred by the Kodokan, all of them to Japanese judoka. This has led to upper level ranks becoming extinct in some arts. In other styles, the dan ranks are not the
Judo in the United States the naval academy. Judo suddenly had its first strong roots in the United States. Yoshiaki decided to return to Japan, but other Japanese Judo participants followed his example. The judo concentration was mainly centered in Washington before World War II, but several centers existed on the west coast, including Tokugoro Ito's dojo in Los Angeles, which was founded in 1910. Judo first entered the Western United States when Dr. T Ito began teaching Judo in Denver in the 1930s. During World War II Judo was banned in many areas due to the Japanese fear; however, a boom followed the war.