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Iaido Boulder | Japanese Swordsmanship

Iaido Tanshinjuku | Boulder, CO

Iaido has been known by many names — Iai, mutual existence, Nukiai, simultaneous draw, as well as Battojutsu, and skill of sword drawing.

Iaido, loosely interpreted as the way of drawing and cutting, is an elegant Japanese martial art that employs a sword as a tool to master one’s own ego. Iaido practitioners learn to control the sword in an effort to control their own minds and reactions to the obstacles and conflicts life presents.

Thursdays 7:30–8:30 pm | Saturdays 7:00–8:30 am
Traditional Japanese Swordsmanship Boulder Iaido Tanshinjuku

Iaido is an ancient art first developed around the 1550’s in feudal Japan. This long tradition has been handed down through the ages in the Samurai warrior class and has a long tradition and culture.


Modern Iaido has been strongly influenced by the Zen philosophy and the teaching of Satsujin Ken Katsujin To — the “sword which preserves life and the sword which destroys.” Today’s Iaido emphasizes “the sword which preserves life” as well as the spiritual, technical, and physical aspects of the art.

Through the samurai class, many styles of Iaido were created and passed down through the generations. The styles taught by Iaido Tanshinjuku at One Dojo Boulder are Muso Shinden Ryu and Toyama Ryu.


Iaido Tanshinjuku is a traditional Iaido school and does not does not teach improvisational or movie styles of sword play

Iaido Japanese swordsmanship Boulder Colorado

About One Dojo Boulder Iaido Instructors

Kent Krumvieda Sensei

Kent Krumvieda is the Head Instructor and Dojo-Cho of Iaido Tanshinjuku. He holds a black belt in Iaido and Aikido.

Reina Watanabe Sensei

Reina began practicing Aikido in 2010 at Aikikai Tanshinjuku under Kei Izawa Sensei and Mariquita Izawa Sensei. Alongside her training in Aikido, Reina also practiced Iaido under Steve Shaw Sensei.


She initially began training in Aikido and Iaido as a way to explore her Japanese heritage, and learn valuable self-defense techniques, practical for a young-woman. Since joining Tanshinjuku, Reina has participated in numerous seminars and demonstrations, and received the rank of Shodan in Aikido and Iaido in 2018. Since earning Shodan, Reina has become an instructor in Iaido, and aspires to further her learning through teaching. 

iaido boulder colorado one dojo

In Memoriam

Steven Shaw Sensei

Steven Shaw Sensei began his training in Iaido under the watchful eye of the late Rev. Kensho Furuya at the Aikido Center of Los Angeles. While there, he trained in Aikido and Iaido where he received the ranks of Nidan and Sandan respectively. As his training progressed, Shaw Sensei assisted with Aikido instruction for the Children’s Aikido program, and beginning Iaido.

In an effort to provide an alternative lifestyle for his growing family he decided to move to Colorado. Furuya Sensei wrote to Hombu dojo in Japan to ask for recommendations where Shaw Sensei should train. Hombu dojo’s response sent Shaw Sensei to train under of Izawa Sensei at Aikikai Tanshinjuku where he soon became a senior instructor in Aikido and chief instructor of Iaido.

Start Iaido Japanese Swordsmanship

Thursdays 7:45 – 8:45 pm

Saturdays 7:00–8:30 am
Thurs, Sep. 21 – Sat., Dec. 2, 2023 (skips Thanksgiving)

10-Weeks | $225

Japanese swordsmanship instructor Iaido Tanshinjuku
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