Its kinda visually awkward to see a hole through the slate when your playing, but as long as the missing piece is not in the playing surface there shouldn't be a problem. I have played on one similar to this, but it was missing one of "ears" of the side pocket. The break came just short of the line where the balls roll down the rail about 6 inches and never bothered the playing surface. Much more commonly found is the slate broke in half or from the side rail across to the end rail, which is usually from the table being picked up and dropped.