“As he takes his stance and addresses the ball, you may note another Hagen characteristic. Since you took up golf you have been told to keep your eye on the ball, but have you ever paused to wonder which eye?┬áThere is a master eye in golf, the same as in rifle shooting, and in most golfers, as in most riflemen, it is the right eye. With Walter Hagen it is the left eye, as with Bobby Jones. Offhand, they are the two leading exponents, so far as my observation goes, of the left-eye style of address–and it is the style that favours the right-hand golfing swing, because with the left eye lined on the ball, the head is naturally turned slightly in the direction the body must turn in the pivot that brings the club back; hence there is less strain in keeping the head in one place as the backswing progresses.”
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O. B. Keeler, “The Style of Walter Hagen: A Close Inspection of America’s Leading Professional” in the American Golfer Magazine (1923)