Wiki-Back plow

This is one of the processes applied to the back of Japanese knives, and refers to the indentation on the back of the knife. By making the indentation, the area where the food comes in contact with the knife is reduced, which in turn reduces friction and improves the sharpness of the knife.

Related websites
Decoding Japanese Knives: Understanding Parts and Names | KIREAJI
Enhancing Japanese Knife Functionality with Urasuki Dimples | KIREAJI