An curved arrow pointing right. Longbows, or Yumi, have been used in Japan for centuries. But today, a handmade bamboo bow can cost over $2,000. At over 2 meters tall, these bows are difficult handle.

Stewart, 59, an Australian, is a champion of one of Japan’s oldest martial arts — kyudo, a traditional form of archery that dates back over 10,000 years. In its most dynamic form, kyudo is ...