When Junichi Takayasu was 3 years old, a picture book about ninjas changed his life forever. What fascinated him most, however, wasn’t the assassins’ stealthy skills or secret gadgets but their usage of a very special plant.

“The book showed how ninjas trained by jumping over cannabis plants,” Takayasu says. “Every day they had to leap higher and higher because cannabis grows very quickly. I was so amazed that I told my mom I wanted to grow cannabis when I was older.”

Understandably, Takayasu’s mother was rather distressed by her son’s aspiration. Japan’s anti-cannabis laws are among the strictest in the world, with possession of even small amounts punished by five-year prison sentences and illicit cultivation earning growers seven years behind bars.

However, Takayasu refused to let this put a damper on his dreams. Today, more than 40 years later, he is one of Japan’s leading experts on cannabis and the curator of Taima Hakubutsukan — the nation’s only museum dedicated to the much-maligned weed. Opened in 2001 in the town of Nasu, Tochigi Prefecture, approximately 160 km north of Tokyo, the museum’s mission is to teach people about the history of cannabis in Japan — a past that, Takayasu believes, has been denigrated and forgotten for far too long.

“Most Japanese people see cannabis as a subculture of Japan but they’re wrong,” Takayasu says. “Cannabis has been at the very heart of Japanese culture for thousands of years.”

According to Takayasu, the earliest evidence of cannabis in Japan dates back to the Jomon Period (10,000-200 B.C.), with pottery relics recovered in Fukui Prefecture containing seeds and scraps of woven cannabis fibers. “Cannabis was the most important substance for prehistoric people in Japan,” he says. “They wore clothes made from its fibers and they used it for bow strings and fishing lines.”

It is likely that the variety of cannabis from which these Jomon Period fibers originated was cannabis sativa. Tall-growing and valued for its strong stems, it is from sativa strains that today’s specially bred industrial hemp is derived. (See sidebar, “What’s in a name?”)