1. Point the blade towards the eyes, so that the surface of the blade forms an angle of 30 with the line of sight. You will see an arc on the blade-a white edge line, indicating that the knife is blunt.

2. First, grind the inner edge surface. Make the kitchen knife and grindstone form an angle of 3 ~ 5 (the smaller the inner edge surface, the more labor-saving it is when cutting vegetables). When sharpening the knife back and forth, keep this angle basically unchanged. Every few dozen times until the blade line is very small. If you continue to sharpen the knife, the blade will curl and the edge line will increase.

3. Grind the outer edge surface again. Make the kitchen knife and the grindstone form an angle of 5 ~ 8 (the outer edge surface ensures that the cut vegetables can be smoothly separated from the kitchen knife, but not too big). When sharpening the knife back and forth, keep this angle basically unchanged. Observe the blade every dozens of times.

I hope the above information is helpful to you.