Yesterday (May 7), the Nikkei stock average jumped 3,320 yen.

The largest single-day gain on record, with a closing price of 62,833 yen marking an all-time high. Apparently, investors rushed into AI and semiconductor stocks driven by the "fear of not owning."

…and what were we private tutors doing meanwhile? Getting ready to start calculating monthly tuition fees as the month-end approached.

While the world is up 3,320 yen, here we are staring down Excel for tuition calculations. Doesn't that seem a little wasteful?

Key Takeaways

Stock prices rise on the "fear of not owning." Tutoring admin work steals time on the "fear of holding on." If you can drop it for $5 a month, you should drop it.

Private Tutors Doing the Opposite of "Fear of Not Owning"

The Nikkei article used the phrase "fear of not owning."

The fear of missing out on a rising market by not holding AI and semiconductor stocks

Makes sense. Investors move out of fear of "losing out by not owning."

Meanwhile, what about us individual private tutors?

Investors

"Fear of not owning"
→ Profit by holding

Tutors

"Fear of letting go"
→ Burn out by holding onto admin work

The spreadsheet for tuition tracking, handwritten lesson records, PDF invoices made at month-end, LINE reports to parents—none of these earn you a single yen by holding onto them.

If anything, the more you carry, the less time you have for lesson prep, and the quality of your teaching drops.

"What You're Holding vs. What You're Losing" by the Numbers

Here's a rough estimate of month-end admin work per tutor.

3-4 hours
Month-end admin (10 students)
12x/year
Every single month
36-48h
Hours lost annually

At 3,000 yen per hour, that's an opportunity cost of 108,000 to 144,000 yen per year.

In Nikkei-gain terms, well, it's nowhere near 3,320 yen, but converted to your own hourly rate, it quietly hurts.

How the Kagemusha System "Streamlines" Your Work

Kagemusha System is a tool that fully automates tuition management, lesson logging, and invoicing for private tutors—all for just 500 yen per month.

The mechanism is simple.

Add lessons to Google Calendar

Just enter "Student Name - Math" in the calendar you already use.

Lessons are logged automatically when finished

Lesson dates, times, and student names accumulate automatically in your own Google Spreadsheet.

PDF invoices generated automatically at month-end

Lesson counts × hourly rate are tallied per student, and PDF invoices are generated with one click.

All that's left is to send

Just attach to email or LINE for parents and your month-end work is done.

All your data stays inside your own Google account. Nothing is sent to an external server. So there's no risk of personal information leaks either.

Manual vs. Kagemusha System (Investor-Style Comparison)

ItemManual (the "hold on" camp)Kagemusha System (the "let go" camp)
Month-end fee calculation2 hours (battling with a calculator)0 minutes (auto-tallied)
Invoice creation1 hour (typed manually in Word)0 minutes (PDF auto-generated)
Lesson loggingHandwritten every timeAutomatic via calendar sync
Calculation errorsAt least once a monthMachines don't make them
CostTime (priceless and painful)500 yen/month

You can drop something that costs you just by holding onto it for 500 yen a month. As a "don't-hold-it" strategy, that's not a bad deal.

Frequently Asked Questions

Is the setup difficult? I'm not great with IT…
It takes 5 minutes. Just log in with your Google account, then enter student info and hourly rates. Zero programming knowledge required.
Is it really 500 yen a month? No additional fees?
Just the 500 yen monthly fee with no additional charges. It's a flat rate regardless of student count or lesson volume.
Where is data stored? I'm worried about security.
Data is stored in your own Google Drive and Spreadsheets. Nothing is ever transmitted to an external server. The system is designed so that no information leaves Google.
Can I use it for tax filing too?
Income is automatically tallied by month and year, so you can use it directly as a sales summary for tax filing. Per-student breakdowns are also generated automatically.

Final Thoughts

The day the Nikkei surged 3,320 yen to set a new all-time high.

While investors around the world are moving on the "fear of not owning," maybe we tutors should be moving on "the fear of holding onto admin work."

If you can buy back 3-4 hours each month—40+ hours a year—for just 500 yen a month, doesn't that sound like a pretty solid "investment"?

At the very least, as an option for ditching that future of wrestling with a calculator at month-end, it's worth knowing about.

About the Kagemusha System

A tuition management and automatic invoice generation tool for individual private tutors. Automates lesson logging via Google Calendar integration and generates PDF invoices with a single click. Everything is contained within your own Google account. Just 500 yen per month, with setup completed in 5 minutes.

→ Check out the Kagemusha System

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