What functional katana steel is the most corrosion resistant?

Hi, I was wondering what steel in a functional katana is the most resistant to corrosion (disregarding the 5-10 thousand dollar ones like L6 Bainite)? My guess would be 9260 spring steel, but I am curious if that is incorrect or if there are any others I am unaware of. Obviously no functional sword steel is truly stainless, but I was wanting to know which one has the most resistance.