Handball JinSharing how to use Sports × AI
I want to rebuild a stronger Japan through knowledge sharing. My goal is to democratize video and tactical analysis so it’s not limited to experts but usable by anyone on the ground.
About Me
I am an indie developer called “Handball Jin,” applying AI technology to sports. A passionate handball player with study/ stay experience in Denmark, I became fascinated by AI after returning to Japan and started applying it to sports.
Aiming to “rebuild a strong Japan through knowledge sharing,” I want to spread top-level handball know‑how in Japan via technology. I call myself an AI-driven entrepreneur; I even declined a major-company job offer to focus on personal development using LLMs.
What I do
Beyond building products, I publish my learnings (e.g., the “HSTATS Board Evolution Diary” on note). As of Oct 2025, HSTATS Board development has ended, but I keep sharing handball insights (e.g., youth development approaches in Europe, video-analysis methods) and working on new products.
My product “HSTATS”
A “video notebook app” to review games and practices efficiently
Overview & Goal
HSTATS lets you tag and comment on YouTube game videos so you can instantly jump to any scene. The aim is an intuitive interface that makes learning from video effortless.
With this tool, student and club teams can easily review footage and share takeaways.
Key features
- ✓YouTube integration & sharing: Use existing YouTube game videos, even unlisted ones, and share/review easily within your team
- ✓Tagging & comments: One click to tag plays and categorize key moments and improvements
- ✓Auto highlight creation: Extract tagged scenes to generate a highlight page instantly
- ✓Cloud & multi-device: Data lives in the cloud so you can access from PC or phone anywhere
Users & scenarios
Target users are student clubs and local teams. Reviewing games with HSTATS helps surface issues quickly.
Players can point out plays to improve using tags, enabling active reflection. Coaches in busy environments can guide efficiently with video.
Pricing & onboarding
At the Dec 2024 launch, all features were ¥0/month for 2024 (early access). From 2025, paid plans start at ¥770/month (early adopter rate).
It’s a web app—just an internet connection and YouTube account are needed to start.
Notice: HSTATS Board development ended
The 3D tactics board app “HSTATS Board,” developed since 2024, was discontinued in October 2025.
We aimed to support 3D tactical understanding beyond 2D boards, but after reassessing practical needs we decided the product no longer justified continuation.
Intent behind development
We wanted the whole team to share the same tactical image through 3D movements and perspective changes.
Building multi-sport usability and play animations taught us a lot about coaching challenges.
Why we ended it
- •We couldn’t secure enough real-world trials to reach everyday use.
- •Many needs were already covered by existing tools; coaches preferred physical boards in practice.
- •Instead of continuing misaligned development, we chose to focus on areas with clearer demand.
Future focus
We’ll shift resources to HSTATS and other high-need areas. Huge thanks for all feedback.
If demand rises again, we may revisit the idea using what we learned.
Contact
For questions about the discontinuation or future work, please reach out via the contact form below.
Philosophy
The origin of HSTATS was the question: ‘Can we give busy coaches an easier way to review video?’ I want to democratize video/tactical analysis so it’s not just for experts.
At the crossroads of handball and AI, I share my journey on X and note. I want young players and coaches to review video easily and share ideas, and to remove the barrier of ‘no budget, no analysis.’
“Fuse my handball experience with cutting-edge tech to transform coaching and learning.”
This belief shows up in taglines like ‘Make video a clear, shareable learning space’ and ‘Tactics in 3D, sharing seamless.’
Contact
Questions about HSTATS, feedback on the discontinued HSTATS Board, or collaboration ideas? Feel free to reach out.
handballasu@gmail.com