Tying up is a way to get even closer to ones opponent without creating a high liability of getting taking down as well as introducing a greater multitude of set ups to use on ones opponent. Some times when the opponent is very strong in the area of tie ups you may put yourself at a liability. It may be easier to use a good setup and take-down without tying up. When you are at an advantage over your opponent in this area it is a good technique. When tying up with ones opponent one should have some kind of game plan otherwise it generally turns into a who has a harder head contest for the duration of that particular period and coach loses his voice and patients, trying to make something of nothing. There are many different tie ups but most common tie up is the collar tie. one moves to many different tie ups from the collar tie as well.