In baseball, the most frequently turned double play. The numbers indicate positions: 6 is shortstop, 4 is second base, and 3 is first base. A runner must be on first base to execute this play, and there must be fewer than 2 outs (duh).
The ball is hit on the ground to the shortstop, who picks it up and throws to second base. The second baseman touches the base to force the first baserunner out and quickly throws to first base. The first baseman catches the ball, touches the base, and boom, double play.
Similar to the 5-4-3 double play, which starts with the third baseman instead.