Prior to first use, you should rinse our knives with hot water.
After every use of the knife, you should take care that the knife is rinsed immediately, without an aggressive detergent, and dried with a soft cloth. For your protection, you should wipe the knife from the back of the cutting edge with a dishcloth or towel.
You should rinse off aggressive substances such as lemon juice directly after use.
Never put the knife in the dishwasher. This affects not only the material but also the sharpness of the cutting edge.
As a cutting surface in principle never use glass or granite slabs. Even though these are easy to maintain, they ruin the cutting edge of the toughest steel. Use only boards (preferably head wood) or plastic boards with medium strength.
You should take care that knives with a natural wooden handle do not remain too long in water. From time to time oil the wooden handle with some neutral vegetable oil.
When you store the knives, watch out that the cutting edge never comes in contact with other metallic objects. Thus, you can avoid that the blade gets damaged. Either store the knives in a knife block, a drawer insert made of wood or, in case of the Japanese blade shapes, in a wooden sheath.