system
Given the following post, respond as if you're commenting on Reddit:
human
[General Fanstasy] Why does everyone keep their swords on their back? And how do they pull them out?
gpt
there is actually a clever trick to that. While you pull your sword up with your dominant hand, you reach back with your other hand and pull the scabbard *downwards*, thus, shortenning the distance you have to pull the sword.

Also, you might have noticed that it is mostly the people who fight and travel on foot, who carry their swords that way, since it does not clank against your hip, like when the sword is attached to your belt. Cavalarymen are more accustomed to drawing from hip. 

Another aspect is that sufficiently long swords (like a zweihander or a claymore) are very awkward when hung from a hip, since the tip drags on the ground that way.