Part 4: How a Tutor with Zero Programming Experience Built a SaaS with AI — The Birth of Kagemusha

Previously

In Part 3: Meeting Claude Code, I wrote about how Claude Code freed me from copy-paste hell and dramatically accelerated my development speed.

As features kept taking shape one after another, a single thought emerged.

"Isn't It a Waste to Keep This All to Myself?"

The system I built with Claude Code was originally 100% for personal use.

I'd add a lesson to my Google Calendar, and it would automatically log to my spreadsheet. At the end of the month, an invoice PDF would pop out — just for me.

Work that used to take 2–3 hours every month dropped to zero.

After one month of using it, it was so ridiculously convenient that a thought hit me:

Aren't there other tutors out there struggling with the exact same thing?

There are tons of independent tutors across the country. And every single one of them must be dealing with the same pain points. Attendance tracking is a hassle. Creating invoices is tedious. But there's no tool that fits just right.

The Name "Kagemusha"

When I decided to turn it into a product, the first thing I did was come up with a name.

The Kagemusha System. A shadow stand-in that handles the tedious work of attendance management on your behalf.

The moment the name was decided, it hit me: "I'm really turning this into a product."

The Wall Between "For Me" and "For Everyone"

This is where things got way harder than I'd imagined.

A tool built for yourself and a product built for others are completely different things.

The biggest challenge by far was the setup problem.

For personal use, opening the Script Editor and pasting in code is perfectly fine. But there's no way I could tell tutors to "please open the Script Editor."

The user shouldn't have to do anything. Press one button and everything sets itself up.

Making this a reality meant diving back into development.

The Challenge of Automated Setup

The core of the Kagemusha System is "automatically building the system within the user's Google account."

In other words, once a user purchases and hits the setup button:

You wouldn't believe how much trial and error it took to achieve this "one button, fully automatic" experience.

A person with zero programming experience, building a system that automatically deploys into someone else's Google account. Honestly, there were many times I thought, "This might actually be impossible."

But Claude Code stuck with me through it all.

The Product Starts Taking Shape

When the automated setup finally came together, I thought, "This might actually sell."

• Purchase is completed entirely online
• Setup takes just one button press
• All you do is add lessons to Google Calendar
• Everything else is automatic

All a tutor needs is a Google account.

¥500 per month. For the price of a can of coffee, you're freed from hours of administrative work every month.

Next Time

Part 5: The Evolution — Integrating payments with Stripe, building a landing page, and completing the automated setup. I never imagined someone with zero programming experience could pull all this off.