The Strike Zone
The strike zone is an invisible box over home plate, roughly from the midpoint of the batter’s torso down to just below the kneecap, and as wide as the plate. A pitch that passes through it is a strike even if the batter never swings. The umpire crouched behind the catcher judges every pitch.
Strikes and Balls
A strike is charged when a pitch crosses the zone untouched, when the batter swings and misses, or when the batter hits the ball foul (with one exception below). A ball is a pitch outside the zone that the batter does not swing at. Three strikes is a strikeout and the batter is out. Four balls is a walk — also called a base on balls — and the batter is awarded first base for free.
The Count
The count is always said balls-first: ‘two and one’ means two balls and one strike. A ‘full count’ is three balls and two strikes, so the next ball or strike usually ends the at-bat. The count shapes strategy: ahead in the count a hitter can wait for his pitch, while behind it he must protect the plate.
The Foul-Ball Rule
A foul ball counts as a strike — but it can never be the third strike. With two strikes a hitter can foul off pitch after pitch and stay alive, which is why some at-bats stretch to ten pitches or more.
Why It Matters
Every plate appearance is a small negotiation over the strike zone. Hitters who swing at strikes and lay off balls reach base more often, and reaching base, as we will see, is the single most valuable thing a hitter can do.