About rust - Recommend knife

I recommend 3 layered, stainless covered knife. It has the cutting taste of carbon steel and you don't need to worry much about rust.3 layered knife, stainless & carbon steel

Core is carbon steel. Sides are stainless steel. Stainless steel is not oxidized. Core material touch the food. It's important for cutting. Stainless covers most of body. Only edge part is not covered. This part will be oxidized and change color.

Explain rust part in 3 layered knife

Even it's oxidized and change color, the function is not changed. It's only visual problem. This color change is a little. Most of people don't mind it. 

After oxidization, change color

This oxidation is very hard to prevent. If you don't want to see this change, you should use stainless 100% knife.