Japan: ribo-barai, and a ceiling that depends on the balance
Japanese cards mostly do not have a minimum payment in the sense the rest of this guide uses. What they have is ribo-barai, revolving payment, where the cardholder sets a fixed monthly amount and the balance revolves behind it. Because the amount does not fall with the balance, ribo-barai behaves like the calculator's fixed-payment mode rather than its minimum mode; the 5% used here is simply the percentage that produces an equivalent opening payment. If you know your ribo-barai amount, enter it under "Fixed amount" instead.
Ribo-barai is heavily marketed, often as a card benefit with bonus points attached, and it is where Japanese card debt is made. A purchase paid in full costs nothing; the same purchase moved to ribo-barai starts accruing interest that a fixed monthly amount can carry for years.
The Interest Rate Restriction Act caps the rate, and unusually the ceiling depends on the size of the balance: 20% on the smallest amounts, falling to 15% on the largest. Card rates therefore cluster just under the applicable ceiling rather than spreading out. Amounts here are in whole yen, which has no minor unit, so the schedule above settles to the yen rather than to a hundredth of one.