First base, or 1B, is the first of four stations on a baseball diamond which must be touched in succession by a baserunner in order to score a run for that player's team. A first baseman is the player on the team playing defense who fields the area nearest first base, and is responsible for the majority of plays made at that base.
In the numbering system used to record defensive plays, the first baseman is assigned the number 3.
The rules of baseball differ slightly from league to league, but in general share the same basic gameplay.
Statistics play an important role in summarizing baseball performance and evaluating players in the sport.
Since the flow of a baseball game has natural breaks to it, and normally players act individually rather than performing in clusters, the sport lends itself to easy record-keeping and statistics. Statistics have been kept for professional baseball since the creation of the National League and American League, now part of Major League Baseball.
A base on balls (BB) is credited to a batter and against a pitcher in baseball statistics when a batter receives four pitches that the umpire calls balls. It is better known as a walk. The base on balls is defined in Section 2.00 of baseball's Official Rules, and further detail is given in 6.08(a). It is called a "walk" because the batter is then entitled to walk to first base, or more specifically (as defined in the rules of baseball) he is "entitled to first base without liability to be put out." However, it is considered a faux pas for a professional player to walk to first base (as opposed to physically running); in all likelihood, observers of any game will see the batter-runner and any advancing runners jog on such a play.
The term "base on balls" distinguishes a walk from the other manners in which a batter can be awarded first base without liability to be put out (e.g., hit by pitch, catcher's interference). It, quite literally, as explained by Rule 6.08(a), means that the batter is awarded a base, on "balls". Though a base on balls, catcher interference, or a batter hit-by-a-pitched-ball (HPB) all result in the batter (and possibly runners on base) being awarded a base, the term "walk" usually refers only to a base on balls, and not the other methods of reaching base without the bat touching the ball. An important difference is that for a hit batter or catcher's interference, the ball is dead and no one may advance unless forced; the ball is live after a walk (see below for details).
In baseball, fielder's choice (abbreviated FC) is a term used to refer to a variety of plays involving an offensive player reaching a base due to the defense's attempt to put out another baserunner, or the defensive team's indifference to his advance. Fielder's choice is not called by the umpires on the field of play; rather, it is recorded by the official scorer to account for the offensive player's advance without crediting him with an offensive statistic such as a hit or stolen base.
Though there are several definitions of fielder's choice, the most common (and the only one commonly referred to as FC) involves a fielder fielding a fair ball and, though he has a clear opportunity to throw out the batter-runner at first base in the official scorer's judgment, chooses to try to put out another baserunner, thereby allowing the batter-runner to safely reach first base. Other plays that fall under the definition of FC are usually referred to using other terms such as "defensive indifference" or "on the throw."
In baseball, an earned run is any run that was not necessarily enabled by a fielding error or a passed ball. In other words, an unearned run is one that would not have been scored without the aid of an error or a passed ball committed by the defense, and an earned run is simply one that is not unearned. An error made by the pitcher in fielding at his position is counted the same as an error by any other player.
Regardless of the name, an unearned run is credited to the offensive team's score the same as any other run. It is only "unearned" in that it was, in a sense, "given away" by the defensive team.