According to a longitudinal study (conducted from 1998 to 2014), the average time taken to get a first-degree black belt is ten years. Of course, this duration differs among martial arts. The shortest recorded training time is four years, while the longest to get a first-degree black belt is twenty-seven years. The study measured the time taken for these martial arts: Aikido, Iaido, Judo, Jujutsu, Karate, Kenpo, Kobudo, Taekwondo and Wing Chun.