system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does a self-sharpening blade sharpens itself?
gpt
Self-sharpening blades have a metal strip along the entire length of the cutter. When the cutter moves through the thing you're cutting, that metal strip is rubbed against the cutter and sharpens. If you're cutting something like paper, it'll work really well.   


There's some debate whether or not this kind of thing actually works or if it's just a marketing gimmick. There's some evidence for both sides of the argument, so really take it with a grain of salt. It's generally going to be better to just sharpen your blades from time to time.