How to shortlist towns
Japan has 1,892 municipalities, too many to compare one by one. The way to cut them down is to add one condition at a time. As an example, this article adds four in turn — flood area ratio, earthquake probability, land price sample count and distance from Tokyo Station — and counts what remains after each, using the real data.
With no condition there are 1,892. A flood area ratio of 5.0% or less leaves 782, and adding an earthquake probability of 30.0% or less leaves 544. Requiring at least 4 land price samples leaves 126, and limiting to 150 km from Tokyo Station leaves 11.
| Step | Add the condition | Municipalities left |
|---|---|---|
| 1 | All municipalities | 1,892 |
| 2 | Flood area ratio 5.0% or less | 782 |
| 3 | And 30-year probability of Shindo 6-lower or above 30.0% or less | 544 |
| 4 | And at least 4 residential land price samples | 126 |
| 5 | And within 150 km of Tokyo Station | 11 |
How to read this table
The first step is to pick only one or two conditions you will not give up. Starting with many conditions can leave zero candidates and no way to tell which condition was too strict. As in the second row of the table, add one and look at the count.
The second step is to check how many remain after each condition. In this example, 418 municipalities drop between the third and fourth rows. They are not dropped because their land is expensive, but because they have too few residential standard sites to compare. Some conditions move the count because of whether data exists, not because of how good a town is.
The third step is to look at the remaining towns on the map and find the ones at the edge of your conditions. A town just over the flood limit, for example, may bring in many more candidates if you loosen the limit slightly. The fourth step, once you are down to three to five, is to open each municipality page and its akiya bank. The fifth step is the hazard map for the address and a visit; the items to look at are in “A checklist for visiting a town you have shortlisted”.
What the numbers do not tell you
The counts are the result for the conditions and limits chosen in this article. Change a limit and the count changes. Move the numbers on the map's filters to match your own criteria.
Municipalities without data are counted as not meeting a condition. Having no data is different from having high risk.
Narrowing down is only a cut before checking in person. A town that meets the conditions is not necessarily a town that suits your life.