FOCUS · FUTURE ORIENTED

Rentaro Hayashi

I think about where we are heading next—and how to get there step by step.

I have a sense of direction. I am here to walk that path with you.

Born: June 16, 1999 · Current roles: Head Tutor, Idai Juku · Saga University School of Medicine · CEO, CRAai Inc.

What would you like to know?

Feel free to explore my background, work, and projects.

See FAQ

News

Updates around my work and activities

Idai Juku official site

Blue planet view
Profile

From past steps to what’s next

Born in 1999. I played soccer from elementary school and went through Sagan Tosu’s youth system up to U18. After that, I shifted my focus to study, starting almost from zero; in 2021 I entered the Saga University School of Medicine. Along the way I launched local events, led Idai Juku as its representative, and served as university festival committee chair. In 2023 I started working with AI and RAG and founded CRAai Inc., to explore new ways of building business and infrastructure.

Strong fields: English, Chemistry · What I enjoy: Soccer, running

Idai Juku tutor profile
The journey to Earth
Education

My work at Idai Juku

As Head Tutor at Idai Juku, I work across the education path—from elementary-level tutoring to medical school entrance exams. Having gone from almost zero to admission myself, I support both strong and struggling students in study and mindset. Remote sessions are available.

Idai Juku tutor profile
Earth from space
Skills

Subjects & expertise

Main strengths: English and Chemistry. I tutor for medical school written exams, interviews, and essays based on my own experience, and advise on balancing sports and study and catching up from behind.

Contact & consultation
Space and Earth
Technology

CRAai Inc.

In 2023 I started working with AI and RAG and founded CRAai Inc. as CEO. We are building systems for self-driving business and expanded economic and industrial infrastructure.

CRAai official website

Pick up

FAQ

Frequently asked questions about me and my work

  • I care about how people learn, how they choose their next step, and how technology like AI can quietly support that.
  • Please contact Idai Juku via their official site or by phone. LINE is recommended. New students are welcome.
  • Yes. Idai Juku offers remote sessions. Contact Idai Juku for details.
  • Yes. I participated in Sagan Tosu’s youth system through U18 on this planet and can advise on balancing sports and academics.
  • I was a soccer player through Sagan Tosu U18, then shifted to study and entered Saga University School of Medicine in 2021. Since then I’ve been involved in education at Idai Juku and in building CRAai Inc.

Contact Idai Juku

What I’m working on

Medical school prep

I support students from written exams through interviews and essays to admission, and help them think about what comes next.

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Sports and study

I went from soccer through U18 to zero-to-medical-school in three years. I share what helped me balance both and choose a direction.

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CRAai Inc.

At CRAai Inc. I work on autonomous business and AI agent infrastructure—the sort of tools I wished existed when I started.

CRAai official website

Let’s think about what comes next

Inquiries welcome: medical school prep, Idai Juku tutoring, or CRAai.

Contact Idai Juku