Odds and Ends
Knights of old
26 1, 1:05pm
I think you are slightly confused here.
If the wall is on the right while you're climbing, then your shield will be towards the defender, who will be somewhat on your left. And it's easy for you to stab towards the left. So this would give an advantage to the climber.
If there even IS a custom for this, then I would assume the stairs would be built such that the outer wall would be on the LEFT for anyone fighting their way into the castle. Meaning anyone climbing up the castle, or anyone descending into the basements.