Representative Scenarios
Loan & Buyer Parameters
Borrower Age at Purchase
28
Mandatory retirement age in Japan: standard age 60/65.
Property Purchase Price
¥55,000,000
Initial Floating Rate
0.85%
Standard Japanese net floating mortgage benchmark.
BoJ 10-Yr Cumulative Rate Hike
+1.00%
Simulates gradual monetary tightening by Bank of Japan.
Building Ratio (vs Land)
60% Structure / 40% Land
Japanese wooden/RC structures depreciate to residual ~5-10% in 25-30 yrs. Land retains value.
Key Japanese Mortgage Facts
• Negative Equity Trap: Because Japanese structures lose up to 90% of value within 25-30 years, 50-year loan paydown is outpaced by asset decay.
• The 78-Year-Old Borrower: A 28-year-old on a 50-year plan will still be servicing debt at age 78—13 years past standard pension start age.
• 5-Year / 125% Rule: Most Japanese banks cap payment surges to 125% every 5 years, converting sharp rate hikes into negative amortization (principal ballooning).
Initial Monthly Outlay
-¥31,450
50-Yr: ¥112,852 vs 35-Yr: ¥144,302
Lifetime Total Interest Delta
+¥16,240,000
50-Year extra interest penalty over 35-Yr
Debt Balance at Age 65
¥18,420,000
35-Yr is ¥0 fully paid off; 50-Yr has 13 yrs left
Underwater (Negative Equity) Window
24 Years
Mortgage balance exceeds property market value
Lifetime Loan Balance vs Property Value Trajectory
50-Year Mortgage Balance
35-Year Mortgage Balance
Depreciated Property Value
Post-Age 65 Debt Cliff
Milestone Life-Stage Equity Comparison
| Life Milestone / Year | Buyer Age | Property Resale Value | 35-Yr Remaining Debt | 35-Yr Net Equity | 50-Yr Remaining Debt | 50-Yr Net Equity | 50-Yr Status |
|---|