Knife Care and Maintenance
Never take it to the dishwasher. There are certain chemicals that harm the composition of your knife whether it be the usual epoxys or whatnot. I have also seen chipping occur when people just pass their knives through a high powered dishwasher. Usually, industrial type dishwashers subject everything to high heat. This may affect the handle structure or any glues used on Japanese knives. Always hand wash your knives with mild soap. Also, never leave it in the sink. You don't want it to chip it just because it hit a plate or a bowl. This is also a dangerous habit that may cut other people using the sink especially in professional kitchens.
People say that if you have a carbon knife, you need to oil it after every use. Based on my experience, you don't need to do it everyday (although it is ideal). You only have to apply food grade oil on your blades if you won't use it for a long time or if your patina isn't that stable yet. Never use oil that you use for cooking. It gets rancid and starts to get gummy and sticky. I personally use Camellia oil or Tsubaki. The most common is to use mineral oil that you could get at drug stores. We do this to reduce oxidation because of the humidity in our surroundings. I have found food grade mineral oil sold as a laxative in Watson's drugstores all across the country. Don't worry, you won't cause diarrhea on your customers. It takes about 45ml of orally digested mineral oil to cause bowel movement. You only need to coat the blade of your knife as thin as possible.
When you store your knife, make sure that it's oiled (carbon knives) and in proper storage. You can either put it in your knife bag with a sheath or just wrap it in a towel if you don't have any and maybe some cling wrap after that. Just make sure that all these are dry. Using a cork for the tip of your knives is also a good idea in case you don't have any wooden or plastic sheaths just to make sure you won't chip the delicate parts.
Always keep your knives sharp, of course. A dull one is a dangerous one and you are most likely to ruin the blade (or your hand) with more downward force applied. Never use sharpening jigs or sharpening apparatuses when doing so. Learn to sharpen by hand to minimize faulty edges or bevels in the long run. You have to start practicing, of course. When sharpening on whetstones, always keep in mind that there is such a thing as over sharpening. Never take out unnecessary metal. You're just reducing the lifespan of your blade. Always check where you abrade metal even after every stroke. Don't just blindly take away metal in search of your burr.
There are also a number of reasons why people chip their blades. The main reason among them is that people tend to over work their kitchen knives. They use it for things that it cannot do. One solid example you may have seen before is when people reach for their knives as though they're can openers. After losing the tip of their knives, they then complain that the knife isn't sturdy enough. This is especially true with thin Japanese blades and more especially on traditional Kataba knives. You just can't expect your thin Japanese knife to perform mercilessly on beef bones as say, your carbon cleaver. For this reason, I always carry a beater knife, a knife I can abuse. I use my Japanese knives for more delicate tasks such as fine slicing and precise dicing whereas my hefty Sabatier gets used for cutting out blocks of parmesan.
Following all these ensures that you get the most mileage out of your knives whether it be made in Japan or anywhere else in the world.
If you have any questions or deem I am missing some pointers, you can email me at firstname.lastname@example.org.