ΔE 19.8, loose: different enough that you should pick on purpose. Sekigahara is noticeably lighter, much more saturated than Ruddy Terra.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Sekigahara is noticeably lighter, much more saturated than Ruddy Terra.
The same difference applies the other way round: Ruddy Terra is noticeably darker, much more muted.
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 Ruddy Terra on the colour wheel See Sekigahara on the colour wheel
All matches: Ruddy Terra equivalents · Sekigahara equivalents