What are the bumps on back your knife?

The bumps on the back of a knife, known as jimping or thumb rests, have several functions:

1. Control: The bumps provide added grip and control when using the knife, especially during precise tasks such as cutting or carving.

2. Safety: Jimping helps prevent the user's hand from slipping forward onto the sharp blade. By providing an elevated surface for the thumb to rest against, it reduces the chances of accidental cuts.

3. Ergonomics: Properly designed jimping can improve the overall ergonomics of the knife, making it more comfortable to hold and use for extended periods.

4. Pressure Application: In certain knife designs, jimping can allow the user to apply more controlled pressure to the blade's spine for specific cutting techniques.

5. Visual Aesthetics: Well-crafted jimping can add an element of visual interest and aesthetic appeal to a knife's design.