Now

What I’m up to these days in a nutshell.

(This is a now page, and if you have your own site, you should make one, too.)

Updated June 19, 2025.

Work

  • I am currently the Head of Applied AI Research at Mercari, Japan’s largest C2C marketplace with over 20 million monthly active users. I founded this team after leading Mercari’s overall AI/LLM product and engineering initiatives for a year, with the goal to focus on more mid- to long-term AI innovation – working ahead of the roadmap rather than outside of it.

  • In my free time, I run Yudemon, a company focused on using creative technology to improve people’s wellbeing and performance. Think mindfulness app + high performance training + media arts project + AI. Currently Yudemon’s main offering is an iOS HRV biofeedback app. The most recent addition to the app is the “Heartwork”, a generative piece of art that is entirely unique for every user, and generated based on the biodata collected during their practice sessions with the app. After pausing the development for a while, I’m currently getting back into it with some big ambitions to bring Yudemon to new platforms, as well as entirely new versions focused on one of my hobbies below (that’s all I’ll reveal for now).

  • I still occasionally give talks or do consulting work around my book Time Off. If you’re interested in booking me, please reach out!

LIFE

  • Sports: After finishing Tokushima Marathon in 2024 in 2:56:11, a time I’m super proud of and that took a ton of work, I’ve been slacking off a little bit. My next running goal is maybe to get back into ultrarunning (KAI 70K in 2025 might be tempting). But Japanese summers are way too brutal to follow any kind of meaningful running training plan, so I just bought a Suito-T smart trainer and road bike and will try indoor cycling to keep my fitness up in the summer

  • Racing: Last year I got really into sim racing (iRacing) and built myself a little sim rig to practice my racing skills at home. I love the obsessiveness of the racing community and the constant push towards perfection, as well as the extreme and sustained focus that’s required. I’m currently practicing a lot in Formula 4 (as well as a little bit with the Porsche 911 GT3 Cup, but I do prefer high-downforce Formula cars), hoping to eventually get into the global top 5% (still FAR off from that). I’m also interested in bringing Yudemon to the motorsports community. I know of several professional athletes and their coaches using it as part of their preparation, but no one in motorsport, and I’d love to change that.

  • I’m going through a bit of an identity crisis as a “writer”. Being a writer was so central to my personality and thought process for so many years, but recently I just haven’t found the time or inspiration or whatever to actually write regularly. How long can I keep attaching that label to myself without writing before it expires? I guess the best solution would just be to actually start writing again.

  • Our dog Kantaro is keeping us busy. He’s through the puberty phase, but still super high energy, so for now just trying to keep him as busy and engaged as possible – a tired dog is a happy dog.