What grit(s) is most important when buying a whetstone?
When considering a whetstone, I always suggest getting a good quality medium grit / sharpening whetstone, which falls in the 400-3K grit range. The grit that most companies focus on is 1K grit. This is the grit that will give your knives good sharpness, but good enough to handle relatively full knives. You will also have the most selections of stones when shopping in this grit rating.