DUAL SWORD WIELDING

Like many teenagers of my age, I am quite a big fan of anime. And in many anime, as well as many western movies, we are introduced to some awesome character who wields not one, but TWO swords. That's like going the extra mile, but it makes sense, right? Double the swords, double the slice and dice? Right?
Wrong.

In one of my trips to Japan (yes, it is heaven.), I had the chance to be a part of a week long course upon sword-wielding. They showed us all manners of swords, from the western classic Long Sword to the northern Great swords to the classic eastern Katana. Like any curious person would, I asked our teacher about the art of dual wielding swords. The teacher looked me straight in the eye and told me simply, “If you go into the battle waving two swords around, you won't be coming out.”

A lot of us, when we put sense into it, might think that dual wielding is indeed impractical. You're using each hand for a separate weapon instead of using both on one weapon, which means you cut your overall cutting-force in half. But hey, that means you can cut twice as many times to make up for it, and if you're strong enough, that won't matter!

But in reality, there is much more than just loss of force behind each swing. You actually lose somewhat around 60-70% of the force you would exert behind a double-handed sword strike when you swing a single-handed dual sword strike. Even if you simply brandish one sword in one hand, you'll be able to exert 40% more force than if you were to carry two in each hands. The reason behind that mainly lies in our muscles relating to the weight of the swords.

Let me tell you from personal experience, swords are not light. Katana blades were lighter than others (they're also very fragile), but they were still unexpectedly heavy. When you're holding one sword with both hands, you have a pivot in between your hands on the handle, which is a key technique in Japanese Kenjutsu. You put your dominant hand over your other hand, which is in most cases right over left. You then pull the sword up over your right shoulder then slash down diagonally, where you have to extend your right hand forward and down while pulling your left hand up and back slightly. The result causes the sword to turn in mid-swing, giving it a lot of power. But when you're using two swords, you cannot use that pivoting action, so you'll have to put in more power from your arms to reach the same force. Even when you're using a single sword, you don't have to worry about moving your other hand too much and end up stabbing yourself, not to mention the balance issues of an added weight swinging in the opposite direction. When you use a shield, you are usually advised to keep it close to your body when you attack with your sword, so your center of mass doesn't move too much. But hold another sword in that hand and you'll have to focus on swinging your attacking hand with enough force, making sure your other sword doesn't stab you and dealing with the other sword's weight pulling your balance off.

So, there goes your (and my own) dream of being the protagonist holding a katana in each hand. Not only is it stupid, it's also impractical. And lets not even start about tri/quad/penta/whatever-wielding.
Pro-tip: Don't dual-wield unless it's an RPG game.