According to Jamie Oliver in his excellent 20-minute meals iPhone App, you need to wash your kitchen knives in cold water, or the edge will go dull.
That’s news to me. I’ve always washed them in the warmest water possible, because I thought it was important to get them clean.
Not so, it seems.
I have a 28-layered Santoku knife from Tojiro-Pro, which I’ve had trouble keeping sharp.
I found out at some point that I was using the steel at a wrong angle (the edges of Japanese knives are at a different angle than European ones), but that hasn’t done the trick. (And yes, I did have it sharpened after learning that, but it’s gone dull again.)
Btw, I love the pattern on these knives.