ΔE 12.1, fair: the same colour family, but not a straight swap. Dark Imperial Khaki is a little lighter, warmer than IJA Nakajima Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Dark Imperial Khaki is a little lighter, warmer than IJA Nakajima Green.
The same difference applies the other way round: IJA Nakajima Green is a little darker, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See IJA Nakajima Green on the colour wheel See Dark Imperial Khaki on the colour wheel
All matches: IJA Nakajima Green equivalents · Dark Imperial Khaki equivalents