Pocket knife

I recently ordered a small pocketknife off Amazon,
and am wondering what should I do to sharpen the blade?
It came pre-sharpened, very sharp.
Brand name Kubey, D2 drop point blade,
after vacuum heat treatment, hardness 60 HRC.
File won?t touch it.
Stone?, crocus cloth?, sandpaper?

Be careful with it, you might not have to sharpen it! I have a couple of Swiss army knives that I have carried for years, never needed sharpening.

A set of diamond lapping stones will do it. One should be 200 grit, and the other 600 grit. Match the original angle where they sharpened it and work both sides. Jim
one example

Japan has some of the nastiest sharp stuff out there. This guy shows you how a nice simple process of sharpening works. Knife sharpening is kinda a ZEN thing. Take your time. When you can cut paper like that you will just glow.
Sharpening

i switched from stones to diamond sharpeners and never looked back, they will wear the blade more but that's the trade-off. i wore a uncle henry out in 2 years skinning squirrels.

Lots of ways to sharpen well, and even more ways to sharpen poorly, as it's one of those subjects where people with no useful knowledge loudly and repeatedly pass on bad information, usually while insisting their method is the only way to do things. I have a good-sized box filled with dozens of stones, but much like ohiojim I prefer diamond sharpeners for most applications. A set of small DMT's like the ones in the link and a leather honing strop (easily made with a strip of leather belt a couple inches wide and as long as you wish--a foot or so for portables and twice that for a fixed one, glued to a flat board and rubbed with stropping compound or even jeweler's rouge from the hardware store) ride in my truck and it makes for a nice portable setup capable of sharpening practically any blade, which can't be said for most jigs. Set your edge and tip profiles and fix nicks on the coarsest stone, then take out the scratches from that initial sharpening with the finer stones and finish by pulling backwards on the strop. Shaving sharp in a few minutes and can then be maintained with the finest stone and stropping unless the edge is damaged.
DMT sharpening stones

Sharpal 165N tow sided, coarse ans 1200.