Khorak, three words:

"Try it yourself"

In the far east where I live, there is a saying, that goes "the spear is the king of all weaponery". Push a spear aside with a shield? That sounds really easy, right?

Wrong. When I was learning kendo, the students would use to have mock duels all the time(which by the way, was forbidden...so we had to do it when the teacher was not around) with one person with a short wooden sword the size of a wakizashi, and the other guy with a plain wooden sword the size of a katana. The difference between the length of these swords are merely about the size of two palms spread apart, and yet "blocking the initial blow" and then "closing in the distance for a stab" was something even a well-trained student could never do.

Things got even worse when the opposition held a broomstick in his hand to simulate a 'spear'. Block a spearhead? Push aside a spear? You wish. As much as you can cast the spear aside with a blow of a sword, the opponent quickly pushes it back - stabbing with the head is only a small part of spear mastery. These guys can hit you senseless just with sides of the spears and that would knock a man out.

The saying would go, "you need to be 3 dans superior to beat a man with a sword barehanded, and 3 dans superior to beat a spear with a sword" The Roman 'standard' method of shield block, step ahead, stab abdomen is in reality an incredible testament of veterancy the soldiers were in, because anyone with even a simple practice in the real thing knows that its a really, really difficult thing to do.