Chess Openings - Semi Slav
The Semi Slav is a very popular opening for black in defense of the Queen's Gambit from white. It is seen at all levels of play and is thought to be one of the more sound defenses against the Queens Gambit. It is similar to the Slav defense, so if you haven't seen that video already make sure you check it out.
chess software used in video can be found at http://www.chesscentral.com and http://www.chessok.com