Sacrifices are divided into two types. One is the sham or pseudo sacrifice, which leads to forced benefit for the sacrificer and another is true sacrifice, which is often used to checkmate the king. The sham sacrifice is always forced and leads to immediate benefit. It is also the more common of the two. Usually it is for material gain, checkmate, or avoiding loss of material. There are deflection sacrifices, destruction sacrifices, simplification sacrifices and siucide sacrifices. Deflection sacrifices deflect pieces. Destruction sacrifices capture pieces and then you take over the square they were guarding. Simplification sacrifices simplify the postion into a winning one for you. Siucidal sacrifices often are used to force stalemate. That is an explanation of the sham sacrifice. I hope you liked it and feel free to edit and comment.