The world of Japanese martial arts mourns the passing of Ninja pioneer, Kameyama Tsutomu, a figure who deeply influenced Japan's traditional ninja practices. Referred affectionately as "Nin-san" by his students and followers, Tsutomu's death leaves a void in the martial arts community. His compelling profile, traditional values, and his relentless commitment to the preservation of ninja arts earned him widespread respect nationally and internationally.

Within Japan, Tsutomu's death has prompted expressions of intense mourning. The nation deeply values its cultural and traditional practices, so ninjas, an iconic symbol of Japanese history, hold a special place in people's hearts. Tsutomu's efforts to preserve this age-old tradition helped revitalize interest in the art, making him highly revered which explains the outpouring of grief following his death.

In the US or EU, figures that have made significant contributions to culturally unique practices are also honored with reverence. The passing of such a figure often leads to wide public admiration for their work, similar to the public mourning and recognition for Tsutomu’s contributions in Japan.