 The first hockey goals were " 7 feet ( 2 @.@ 1 m ) tall posts placed 6 yards ( 5 @.@ 5 m ) apart " but were reduced to 4 yards ( 3 @.@ 7 m ) apart in the 1886 rules . In 1987 , a rule was introduced so that at penalty corners " the first hit at goal should not cross the goal @-@ line higher than 18 inches ( 460 mm ) " . This saw the introduction of a sideboard and backboard to the goals which are now mandatory . 
