Dang, wish I had known that there was a knife place in Wan Chai, was there back in November and never saw it.
There are three places that I saw knives in Hong Kong, there is a shop that sells lots of tactical folders in Ocean Terminal (a mall) in Tsim Sha Tsui, think it was on the 2nd floor, near a supermarket (follow the green signs). Don't remember the name, sorry.
Then there is a Victorinox shop in the Airport near departures, sells some not bad stuff, some good tactical folders.
And lastly for local color, Shanghi Street on the West side of the Kowloon Peninsula, around Yae Ma Te (spelling?) has lots of shops that sell kitchen knives. Lots of serious, 1/4 inch thick, Chinese choppers, laminated steel sushi knives, that sort of thing. If you go looking for a sushi knife make sure that you stop walking north before you get to Mong Kok or you WILL be in brothel country (look for the pink and green neon

)!
hope you have a good trip
Chris