I generally don't. Not that it's a bad thing to sharpen them up. Our late friend, Dannyinjapan, used to talk about how some Japanese swords used in full combat were not all that sharp to keep the durability of the blade in check. I have no way to verify that, but it makes a little bit of sense.
My HI kat and Manjushree aren't the sharpest, but those beauties will cleave with lethal effect.
This is interesting I might have to give this a trytried a bunch of things until I ended up here and feel like that I wouldnt have to buy another system for quite a while.
They even have thin stones which can follow Kukris' kurves.
This is what I find most effective for mine.
This guy helped me out a lot. This is ony part B, but part A should be in the suggestions. I've used this method and it is definitely the fastest and will give you an ultra-sharp, yet very strong, convex edge. Which is ideal for katana or other cut-oriented swords. Hope this helps.