The Object of the Game
Two teams of nine take turns batting and fielding. The team at bat tries to score runs by hitting the ball and advancing a runner around four bases and back to home plate. The team in the field tries to record three outs to end the half-inning. After nine innings, whoever has more runs wins.
Balls, Strikes, and Outs
A pitcher throws toward home plate and a batter tries to hit it. A strike is a pitch inside the strike zone, or any pitch the batter swings at and misses; three strikes is a strikeout. A ball is a pitch outside the zone that the batter lets go; four balls is a walk, and the batter is awarded first base. A batter is also out if a hit ball is caught before it lands, or if a fielder holds the ball at a base before the runner arrives.
Around the Bases
A runner must touch first, second, third, and home in order. A single advances the batter one base, a double two, a triple three. A home run clears all four bases at once, scoring the batter and every runner already on base.
Innings and Winning
Each inning has two halves: the away team bats in the top, the home team in the bottom. Three outs end each half. If the score is tied after nine innings, the game continues into extra innings until one team leads at the end of a completed inning.
What to Watch For
The count (balls-strikes), the number of outs, and who is on base. Those three facts explain almost every decision a manager makes — and every probability the Ra model weighs.