The penalty corner has always been an important part of the game, that importance has become more pronounced since artificial turf became mandatory for top-level competitions in the 1970s. The Netherlands' Paul Litjens was the former leading international scorer with 267 goals in 177 matches and was a specialist in hitting goals from penalty corners. Litjens and early specialists were accurate, hard-hitters of the ball; however, the introduction of the drag flick to counter the goalkeepers that lie down during the hit became the favoured technique. This led to the introduction of experts in this skill and Litjens' record was surpassed by Pakistani player Sohail Abbas who is often described as the "world's best" penalty corner and drag flick specialist. India's Sandeep Singh is also regarded as one of the best and has the fastest drag-flick at . The importance of penalty corners has drawn criticism, with the proportion of field goals scored through open play reduced as attackers look to create a foul in the penalty circle, particularly from defenders' feet, rather than shooting directly.