"The bat handle, for not more than 18 inches from the end, may be covered or treated with any material (including pine tar) to improve the grip. any such material, including pine tar, which extends past the 18-inch limitation in the umpire's judgement, shall cause the bat to be removed from the game. No such material shall improve the reaction or distance factor of the bat."
Rule 1.10(b) Official Rules of Baseball, 1983
Jul 24, 1983 the Kansas City Royals trailed the New York Yankees 4-3 with 2-outs in the top of the ninth at Yankee Stadium. George Brett stepped to the plate and hit a 2-run home run off of pitcher Goose Gossage to give the Royals the lead.
Before Brett could cross home plate, Yankee manager Billy Martin came charging out of the dugout ordering the umpire to check Brett's bat. The umpire did so and determined that the pine tar extended beyond the 18-inch rule and nullified the home run and ejected Brett from the game for using an illegal bat. Brett's reaction has become a baseball legend...
The Royals filed a protest and the American League president Lee McPhial upheld their protest and ordered the game to be resumed on Aug 18. Kansas City would hold their re-instituted led and defeat the Yankees 5-4...
