ΔE 15.0, loose: different enough that you should pick on purpose. IJN Deep Dark Green is a little darker, much more muted, warmer than Storm Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). IJN Deep Dark Green is a little darker, much more muted, warmer than Storm Blue.
The same difference applies the other way round: Storm Blue is a little lighter, much more saturated, 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 Storm Blue on the colour wheel See IJN Deep Dark Green on the colour wheel
All matches: Storm Blue equivalents · IJN Deep Dark Green equivalents