HEAD TO HEAD
Japan vs South Korea
Verdict
Japan holds a 61–39 advantage over South Korea on the Relative Advantage Index, a clear margin.
The margin is driven by military spending (57% of the combined total, $62.2bn) and economic size (GDP) (68% of the combined total, $4.0tn). South Korea leads on active personnel.
1 factor — nuclear warheads — could not be scored because the figure is unpublished for at least one side. Those factors are excluded and the remaining weights renormalised, never substituted.
Factor by factor
| Factor | Japan | Share | South Korea | Weight |
|---|---|---|---|---|
Military spending SIPRI Milex | $62.2bn | 57%43% | $47.8bn | 33% |
Economic size (GDP) World Bank WDI | $4.0tn | 68%32% | $1.9tn | 27% |
Active personnel COW NMC | 247.0k | 31%69% | 555.0k | 20% |
Logistics & power projection OurAirports | 270 | 88%12% | 38 | 20% |
Shares are each side's portion of the combined total for that factor. Weights are renormalised across the factors both sides publish — see the methodology. Data read 2026-10-22.
