| Rank | City | Score | Risk level |
|---|---|---|---|
| 1 | Osaka | 100/100 | MINIMAL |
| 2 | Hiroshima | 100/100 | MINIMAL |
| 3 | Nagoya | 100/100 | MINIMAL |
| 4 | Fukuoka | 100/100 | MINIMAL |
| 5 | Sapporo | 100/100 | MINIMAL |
| 6 | Tokyo | 87/100 | MINIMAL |
How are these scores calculated?
Each city is assessed by identifying the most plausible nearby strategic target (military bases, government centres, energy facilities), then modelling blast overpressure, thermal radiation, prompt radiation and wind-driven fallout using scaling relationships from Glasstone & Dolan's The Effects of Nuclear Weapons (1977). The four effects are combined into a 0–100 safety score.
Disclaimer: Research-grade estimates only. Follow official civil-defence guidance in any emergency.