Chukan

The chukan type of apex is used in the informal upright style of bonsai to create a naturalistic and balanced appearance that is slightly to the side of the center of the trunk's entry into the soil. The branches are asymmetrical and irregularly spaced, and the apex is also broad and dome-shaped, but with some variation.  The chukan apex is formed by bending a branch near the top of the trunk into a circular or oval shape, with the stronger growth on the outside of the bend. This creates a rounded crown that fills in the empty space and contrasts with the curves of the trunk. The chukan apex can be achieved by wiring and pruning the branch carefully, and replacing it gradually with new growth as the tree develops.    This style is suitable for deciduous trees that have a curved or slanted trunk, such as maples and elms.