IJA #1 Hairyokushoku (Grey-Green) vs Sky Type S

How close are they?

ΔE 7.3, close: similar, with a visible difference side by side. Sky Type S is a little darker, more saturated, cooler than IJA #1 Hairyokushoku (Grey-Green).

Can I use Sky Type S instead of IJA #1 Hairyokushoku (Grey-Green)?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Sky Type S is a little darker, more saturated, cooler than IJA #1 Hairyokushoku (Grey-Green).

Can I use IJA #1 Hairyokushoku (Grey-Green) instead of Sky Type S?

The same difference applies the other way round: IJA #1 Hairyokushoku (Grey-Green) is a little lighter, more muted, warmer.

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.