first baseman causing balks

Question
Does the first baseman need to be within tagging distance of the runner to receive a throw over from the pitcher ? Is it a balk if the first baseman is behind the runner by a considerable distance or in front of the runner , near the grass cut out, again a considerable distance from the runner and the pitchers throws to him.....is this a balk ???
if so, can you give me a rule # or location to gather this info ?  Thanks, Ron

Answer
Ron,

Official Baseball Rules do not specifically state the rule, but it has been interpreted that the pitcher must throw to the base and not the fielder when attempting a pick-off at first.

The rule used is 8.05(b): The pitcher, while touching his plate, feints a throw to first base and fails to complete the throw;

While the rule doesn't state it, interpretations agree that the ball must be thrown to first. In your example, if the umpire's judgment is that the ball was not thrown to the base, regardless of the fielder's position, it is a balk.