Each spring, I remove the strong apical buds to encourage the weaker internal buds to develop. These side buds create new twigs and smaller leaves which leads to an increase in density.
In June of 94, this tree won the best of show price in the annual Berlin Bonsai Societies exhibition. The tree was growing vigorously and later in June, I defoliated the tree completely. It worked perfectly, the photo is from September 94 and shows nice autumn colors.