mrpcakesThe best way to sharpen any knife, if you don't really know what you're doing, is to hire someone else to do it for you. Sharpening knives, actually sharpening, as in, removing material to give it an edge, can be quite dangerous, as it produces small pieces of flying metal (assuming you're using power tools instead of a whetstone). And unless you're familiar with what you're doing it's easy to make a bad edge, or an edge that won't last.
mrpcakesFor japanese kitchen knives, use a waterstone/whetstone (a sharpening stone designed to be used while wet). I use a 1200/8000 grit combination stone from http://www.epicedge.com/shopdisplayproducts.asp?id=176&cat=2%2E+Combination+Grit+Waterstones
You should definitely watch some videos on proper usage first on youtube as you could mess up your knives/stones. It takes some practice but one can eventually get the hang of it.
Or you could just send them away to a professional... but, careful who you send it to.
BobbitsThat's not how knife sharpening works. The first phase of sharpening a knife is to remove material to make the proper angle. In the modern day you do that with a belt sander.
DarkingA water stone will remove material just fine. I use one and can tell you first hand. Japanese knives are so thin that power tools are a bit too extreme. If that's how you sharpen your knives, fine you have every right to, but it is probably going to remove more material than you need and mistakes will be much less forgiving. I just wouldn't recommend it to anyone especially starting out. Even if I was going to have my knives professionally sharpened, I would never send them to someone using power tools.
BobbitsAgain, not how this works, to make a blade that will stand up to cutting you have to use various levels of roughness in the process of finishing the blade, adding more polish and a finer edge with more fine grain. Using a Whetstone will sharpen the edge, but won't give you a durable one. Again, I would recommend a professional and reputable knife sharpening service.
BobbitsIt's not water, it's whet, as in, to sharpen. And one pass with a whetstone takes a long time to do properly. Using multiple stones would be an arduous task.
DarkingThere are different types of sharpening stones aka whetstones. The most common one for westerners would be an oil stone. The traditional Japanese method uses a water stone. Water stones are soaked in water before use, they are much softer, and they will remove material much faster. That is because they are made out of a different material.
For some of the differences see https://www.sharpeningsupplies.com/Difference-in-Sharpening-Stone-Materials-W51.aspx
DarkingI have a set of globals and power tool would never ever go near that blade. Take to time to learn how to use a stone. Edge will stay sharp for 4 months of everyday use.
DarkingWork as a firefighter. Knives get used but up to 25 different guys some days 3 different meal preps. I also sharpen the entire battalions knives and have been doing so for 3 years. The knives we used to get professionally sharpened from a company that services restaurants used to last only one month, if that, under those conditions.