ΔE 7.2, close: similar, with a visible difference side by side. Dark Flesh is a little darker than Japanese Brown.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Dark Flesh is a little darker than Japanese Brown.
The same difference applies the other way round: Japanese Brown is a little lighter.
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 Japanese Brown on the colour wheel See Dark Flesh on the colour wheel
All matches: Japanese Brown equivalents · Dark Flesh equivalents