Yes Thad explained it pretty much as good as it can be explained! I prefer the 4 b/c it cannot be scared away and can rape the board. Here is an example. You have a 5 left i have a 4 left with 3 of my sappers. If I place my 4 on the left side of teh board you must have your 5 there as well. other wise I have free reign of that side of the board. Adn if you decided to keep your 5 on the other side i road block you with one sapper. and prevent you from getting in. Now at this point in the game i ahve 3 pieces that your 5 will fear. but you have only one piece that i fear!