Real Estate by the Numbers
Japan Edition · Landlord Sim
Only for iPhone
$9.99 · Designed for iPhone. Not verified for macOS.
iPhone
Designed by a working landlord — a US Certified Public Accountant who holds the CCIM designation, with over ten years of rental operations.
In real estate, one bad decision costs tens of millions of yen. Here you can get it wrong as often as you like, for the price of one book, learned by playing rather than reading.
No characters, no gacha, no ads, nothing more to buy.
You start in January 2020 with only cash, pick a run of 5 to 30 years, and finish on net worth.
Two AI investors want the same listings.
■ What a month looks like
1. Read the listing — price, gross yield, cap rate, gap to market
2. Look inside — income, depreciation, cost-approach value
3. Choose the financing — five lenders, five sets of terms
4. Buy, or walk away — first-come or sealed-bid
5. Move on — rent, repayment, repairs, tax
Most months you buy nothing. That is a decision too.
■ Decide by the numbers, not by feel
- IRR — the annual rate over your hold, including the sale
- CCR — annual cash left over, against your equity
- FCR — what the property earns without debt
- K% — annual debt service, against the loan
- DSCR — how far rent covers the payment
When CCR > FCR > K%, debt works for you.
When that order breaks, the return on your own money falls — negative leverage.
Gross yield alone never shows the break.
■ The bank is the real opponent
- City bank — cheapest, lends only half the price
- Regional bank — balanced on rate, term, LTV
- Credit union — high LTV, shorter term
- Non-bank — near-full loans, longest term, highest rate
- Developer-tied — loose underwriting, costs in the price
Outbid a rival and your cap rate drops, your K% rises, and the bank walks away.
■ Where you buy decides where you end up
- Central Tokyo — rent grows 4% a year, but cap rates are barely 3%
- Rural — near 9% yields, but rent falls 1-2% every year
- Okinawa — prices and rent both climb, but salt and typhoons make repairs heavy
■ The numbers cannot be fudged
Cash flow statement, income statement and balance sheet close every month across the whole portfolio, following the practitioner's cash flow tree: GPI to EGI to NOI to before-tax to after-tax.
Profit rising while cash falls is what depreciation running out looks like.
■ Buying is not the only move
- Renovate — value rises only if ROI beats the cap rate
- Build from land — no rent while building, and one in three runs late
- Sell — market price is current NOI over cap rate
Policy rates reset every January, and every 8-11 years something breaks.
It usually lands mid-build, and payments never pause.
Run out of cash and you go under; profitable on paper is not enough.
■ Built for people starting out
Nineteen chapters and a glossary are built in, reachable from the ? in the corner, and every term is spelled out before it is used.
Starting equity runs from 10 to 100 million yen.
■ Why this exists
The developer's background is corporate advisory — M&A due diligence, corporate strategy, and setting up real estate funds. The CCIM designation came from learning that analysis systematically.
Today more people pick a property on the headline yield and whether the loan comes through. In Japan, population and the local economy differ hugely by area, so getting the entry wrong makes both the operation and the exit hard.
Build the criteria once and they last a lifetime.
■ Also
- Japanese, English and Simplified Chinese
- No network access. Works offline
- No personal data collected
- Paid once. No further purchases, no ads
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An educational simulation game, not investment advice. Properties, companies and lenders are fictional; figures simplified.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
- Loan offers now show a projected IRR (10-year hold, exit cap = entry cap, pre-tax)
- Banks sit side by side, so you can compare one building on different terms
- Added a dead cross tile (principal repaid minus depreciation)
- Tap it for a forecast of how many years until it arrives
- Fixed depreciation still counting on buildings whose depreciation had run out
- Fixed some Chinese text showing in the wrong language
- The start screen had two links to the manual; now one
The developer, Watermelon Investments LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- WATERMELON INVESTMENTS LIMITED LIABILITY CO.
- Size
- 5.4 MB
- Category
- Simulation
- Compatibility
Requires iOS 14.0 or later.
- iPhone
Requires iOS 14.0 or later. - iPod touch
Requires iOS 14.0 or later. - Mac
Requires macOS 11.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- Japanese
- Age Rating
4+
- 4+
- Copyright
- © 2026 WATERMELON INVESTMENTS LLC
