Great sword might not be the best example though. I'm not sure there's any way to sheath a weapon that's as tall as you are without looking extremely silly. The best you might be able to do there is a small harness on the character's back that it hangs from.
I once read a very interesting article that made the argument that any sheathing of a blade on the back longer than a shortsword was completely the work of fiction.
That is to say, from a fantasy/fiction standpoint it looks cool to draw your huge sword from your back, but physics prevent it from actually occurring. Your arm is simply not long enough to make the draw.
...I came across this article whilst trying to figure out why I looked so silly trying to draw a hand-and-half sword, and what I was doing wrong. That was with a 3 foot blade I might add(46'' overall), not anything so huge as a claymore.
Baldrics (belt with a loop over one shoulder, to carry weapons) may well have been common in medieval times for larger swords, but for travel; not in a situation where you needed your weapon quickly.
Square Enix when ToAU first went live wrote:
The TP information included in "physical" blue magic spells is only
applicable when using the job ability "Chain Affinity."