The coating is Kalguard and appears to be more durable than other "black" coatings in its ability to resist wear.
The A2 is a carbon steel and therefore not as corrosion resistant as stainless steels.
Rinse it with water after use, especially contacts with salty or acidic material. This includes fruits and other "innocent looking" things that we cut.
For use other than food, I like motor oil. That's right, motor oil as it has many good things in it that fight corrosion. For a knife that will cut food, I am partial to mineral oil from the pharmacy. Tuff cloth and marine tough cloth are also good products and have a following with Forumites.
I think that rinsing and wiping, as a habit, is a good practice with all knives, especially carbon steel blades. A coating of oil, as aforementioned, is good practice paying special attention to the grind area that is not Kalguard protected.
I'm no expert, but this works for me. Note: I do not use my CRK One Piece Range Knives in and around salt water (i.e. diving, fishing and the like). This is not to say that you can not, only that my experience are void of this type of use.
Happy hunting.