The «Pine Tar Rule» is a baseball rule that states that a batter’s bat cannot have more than 18 inches of pine tar on it. The rule was created in 1983 after Yankees player, George Brett, used a bat with an unusually high amount of pine tar on it. The rule states that if a bat has more than 18 inches of pine tar, it is considered an illegal bat and the batter is not allowed to use it. The pine tar must be on the lower 18 inches of the bat handle and must not extend beyond it.