Kyudo AI

Kyudo AI is a smartphone app that watches an archer shoot, detects kai (the full draw, held still before release), scores the form, and says what to fix. Every frame is processed on the phone and the video never leaves it, so it works in a dojo with no network connection. Its Japanese tagline translates as “Just stand up your phone and shoot.”

Where it came from

I built the first version in my second year partly to surprise the teacher who kept pulling me into research and also advised the kyudo club, and partly so its students could check their form without waiting for a coach. With Tomonari Masuzaki and Takahiro Makiyama I presented the method at SJCIEE 2025 as a web implementation; it received the Outstanding Presentation Award, and a fair criticism: the coaching text came from an external language-model API that plainly could not coach kyudo. That is why I started building my own models.

High-school kyudo has about 65,000 athletes in Japan, the most of any budo club sport, but coaching happens a few times a week for a few minutes per student, advisors are transferred, and club activities are moving out of schools. Kai lasts a few seconds; advice rarely arrives in time.

How it works

The phone runs pose estimation on the camera feed, finds the kai phase in the pose sequence, and scores the form from the joint positions. The web prototype was unusable in a dojo without a connection; the app runs offline, and its scoring no longer depends on camera distance or image resolution. The Yuge College kyudo club supplied real shooting data and customer interviews. Students who followed its advice have told us their hit rate went up: user feedback, not a controlled study, but a sign it can support both evaluation and training.

What it led to

In August 2026 Kyudo AI was a finalist in the Youth Pitch Contest at the Startup World Cup 2026 Kyushu Regional (Pegasus Tech Ventures), with Shoei Nishimura. In September 2026 it won the Grand Prize at Lean Launchpad Nagoya 2026, a Tongali program, with Uryu Den and Keito Inoshita, which sends us to the national final in March 2027. During the program we interviewed the club and used Jobs-to-be-Done theory to re-examine what its members need from the app.

I am the team representative. Nothing is on sale yet; next comes calibrating the scoring on real shots and finding pilot schools and dojos.