runner attempts to steal the next base but is tagged out before reaching it safely, he is caught stealing. An illegal attempt by the pitcher to deceive a runner, among other pitching violations, is called a balk, allowing all runners to advance one base without risk of being put out. Another fundamental tenet of the rules of baseball is that a runner who was initially ruled out can subsequently be ruled safe, but once a runner is ruled safe he cannot be called out on the same play, unless he overruns the base. For example, if a baserunner steals second base, beating the throw, an umpire might make the quick call of safe, but if the runner then slides beyond the base and is tagged before he can retreat to it the umpire has the right to change the call. A runner initially called out can be subsequently ruled safe if the fielder putting the runner out drops the ball (on either a tag or force play), pulls his foot off the base (in the case of a force play), or otherwise illegally obstructs a runner from reaching a base that he otherwise would have reached safely. Batting and base running strategy The goal of each batter is to become a base runner himself (by a base hit, a base on balls, being hit by the pitch, a fielding error, or fielder's choice) or to help move other base runners along (by another base hit, a sacrifice bunt, sacrifice fly, or hit and run). Batters attempt to "read" pitchers through pre-game preparation by studying the tendencies of pitchers and by talking to other batters that previously faced the pitcher. While batting, batters attempt to "read" pitches by looking for clues that the pitcher or catcher reveal. These clues (also referred to as "tipping pitches") include movements of the pitcher's arms, shoulders, body, etc., or the positioning of the catcher's feet and glove. Batters can attempt to "read" the spin of a ball early in the pitch to anticipate its trajectory. Batters also remain keenly aware of the count during their at bat. The count is considered to be in the batter's favor when there are more balls than strikes (e.g., two balls and no strikes). This puts pressure on the pitcher to throw a strike to avoid a walk so the batter is more likely to get an easier pitch