system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why was it better for swords to only have ONE edged blade (like the Katana or Falchion)?

Just wandering if it was better at all, or if there are disadvantages to having both blades edged.
gpt
Swords were designed for various purposes. Double edged blades were used to impale or stab the opponent. Whereas katanas are curved and one sided to provide a better slicing motion. 
The shape of the blade provides structural strength. To simplify, the cross section of a katana would resemble a triangle. Impacting a triangle on a point would distribute the force and stop the blade from breaking.