The
four-seam fastball is the most basic
pitch in
baseball. It is straight, hard, and fast. The four-seam fastball is gripped with the
index and
middle fingers across the
horseshoe part of the
ball, where the
seams are farthest apart. It is called a "four-seam" fastball because the fingers touch the seams in four places.
The four-seamer is the fastest, straightest pitch in baseball. It is also the easiest pitch to throw and places the least strain on the pitcher's arm. It will not fool anybody, but it will get to the plate in a hurry, with a good chance of going where it was intended to go. Pitchers throw the four-seam fastball when they want to get ahead in the count, want to try to blow away the hitter with pure speed, or are in a situation where they desperately need a strike and don't have confidence in their breaking pitches.
Also note that there is another way to grip the four-seam fastball, by gripping the ball where the seams are closest together instead of the horseshoe where they are farthest apart. This grip is often used by children, because their fingers aren't long enough or strong enough to grip the seams when they are farther apart, and is also the grip most often used by regular fielders when they need to make a strong, quick, accurate throw.