User blog comment:Master Sima Yi/Assassinews 03-03-'13 — Assassin's Creed IV: Black Flag trailer and screenshots/@comment-5019018-20130313002154/@comment-1379990-20130313024717

A trained swordman could hold a sword like that. It's like holding daggers, which can be more flexible especially when you're holding two swords, one in reverse and the other not. If you're surrounded by enemies it's easy to stab back, while striking at others in front of you. Holding swords in reverse is also more used for slashing, rather than stabbing, so for a curved sword it surely serves a purpose, as you would rather slash, rather than stab with those.