Masaaki Hatsumi shows his disciples from across the world his ninja techniques. (Video by Kana Yamada)

In an "unstealthy" fashion, many muscular people arrive at a home in a residential area in Noda, Chiba Prefecture, at a little past 6 p.m. on a weekday in late November.

After passing through the entrance to the house, more than 100 men and women sat in a circle in a large room on tatami mats.

This horde of people from overseas had converged on this dojo to learn the martial arts of the ninja.

Most were non-Japanese ninja trainees who came from the United States, Germany, France, Canada, Russia, Colombia and elsewhere across the globe.

The interest attests to the popularity of the sneaky undercover agents, which is spreading throughout the world, with a wide range of books themed on ninja having been published in Europe and the United States.

The Bujinkan dojo is run by Masaaki Hatsumi, 86, a martial artist who has mastered skills of nine schools, including the Togakure-ryu “ninjutsu” ninja technique school.

Although ninja used a wide variety of skills, Bujinkan focuses on the fighting techniques of the agents to establish a modern version of ninjutsu. The dojo is flooded with overseas people who visit there for ninja training on several occasions a year.

When that day’s practice started, a male disciple thrust at Hatsumi with a wooden sword. The moment the ninjutsu master dodged the attack and softly touched the wrist of the opponent, the trainee was thrown on the tatami before he knew it.

“Master Hatsumi disappeared the moment he dodged my assault,” said the disciple.

Hatsumi learned judo and other martial arts from his childhood, and mastered Togakure-ryu at age 42 after 15 years of training.

When he turned 50, Hatsumi traveled to the United States to correct the mistaken assumption that ninja were simply assassins. Hatsumi has since toured the Americas, Europe and Africa for 25 years to teach ninjutsu.

He now has many disciples across the world.

One of Hatsumi’s students, a 47-year-old man, who is from Argentina, said it was his third visit to Japan in 2017 alone.

“I have studied ninjutsu for 31 years,” he said. “I initially started learning it simply to protect myself, but have begun thinking of what life should be like.”

Hatsumi said the culture of ninja does not just involve how to defeat opponents.

“Learning ninjutsu or other traditional martial arts of Japan is a way to contemplate how to live and to control one's own life,” he said.

NINJA RESEARCH ADVANCING

Mie University opened an international ninja research center in Iga, Mie Prefecture, which is well known for the Iga ninja clan, in July 2017.

Feodor Kubasov, 31, a Russian researcher, studies the history of the feudal-era secret agents by collecting ancient documents throughout Japan.

Kubasov became interested in ninja when he was 7, learned Japanese history at Saint Petersburg University and came to Japan in 2007 to focus on studying ninja at Mie University.

According to Kubasov, a wider range of books featuring ninjutsu have been published in Europe and the United States than in Japan. In Moscow, an event themed on the Tensho Iga no Ran war between Oda Nobukatsu (1558-1630), a son of Oda Nobunaga (1534-1582), and the Iga ninja clan, will be held in August this year.

“Ninja research is actively conducted across the world, but most researchers are amateurs,” said Kubasov. “I am involved in research as I believe learning the history and studying based on proper methodology are important.”

Meanwhile, Yuji Yamada, a senior official of the research center who is also a professor of ancient and medieval Japanese religious history, has been touring more than 10 countries, including Mongolia, China, Britain, the United States, Spain and Bulgaria, since 2012 with Jinichi Kawakami, the 21st head of the Koka-ryu Banto ninjutsu school, who serves as a specially appointed professor, and others to hold lectures about the history and spirit of ninja.

They held lectures in two cities in Vietnam in November 2017, with 1,500 young people and others attending.

Mie University is planning to introduce a special course and seminar themed on ninja and ninjutsu at its graduate school in the next fiscal year that starts in April. In February, researchers from Japan and abroad are expected to hold a gathering to set up an international ninja society.

NINJUTSU FOR BUSINESS MANAGEMENT

The practice of ninja is attracting attention in the U.S. business world as well.

A book titled “Ninja Innovation” has recently been released, which espouses that Apple Inc. co-founder Steve Jobs, Microsoft Corp. co-founder Bill Gates and other successful entrepreneurs have the ninja spirit, and that business people should learn it.

According to the book, ninja could effectively collect information, overcome difficulties to achieve their missions, and try again and again without fearing failure. Such a way of thinking will lead companies and other organizations to success, the work argues.