In Japan, there was a need for qualified individuals to carry out illegal activities such as covert operations, assassinations, and intelligence gathering. There were samurai who possessed the skills to meet this need. However, it was essential that the samurai’s reputation not be tarnished. In the 15th century, ninjas were created to fulfill this illegal need. However, the Japanese people—including the ninjas themselves—did not accept ninjas who engaged in such dirty work. Over time, many myths and cultural narratives were built around the concept of the ninja. This concept was elevated to a much higher level than it actually was. The number of ninja films—classified as martial arts films—began to increase starting in the 1950s. First, the popularity of martial arts films grew, and then, following the release of Bruce Lee’s four films, which elevated interest in all martial arts to a new level, ninja films experienced a major boom in the 1980s.