blocking in combat

How do you 'block' in combat? I've heard of players using this technique and reckon it would be pretty handy to know.

Here is a tutorial.

http://forum.thesettlersonline.net/t...cking+tutorial

Here is a video.

http://youtu.be/jFb9e7nA4j4

Cheers all. Your input has been much appreciated. It clears things up for me.