The numerous styles of bonsai have been developed over centuries. Some bonsai tree species are better suited to particular styles, and specific techniques may be required. Many styles and sub-styles can become combined, allowing the bonsai artist to bring their own expression to the result. With expertise, occasionally even opposing styles can be blended together to create a successful outcome. Classical bonsai styles are determined primarily by the shape of the trunk of the bonsai tree. There are six classical styles of bonsai.
Formal Upright Bonsai
The formal upright or chokkan style has a vertical trunk that consistently tapers from the base of the trunk to the top of the tree. The branches of the tree are evenly spaced around its trunk. Various arrangements of the tiers of branches can be made to create attractive effects. Conifer bonsai trees are the popular choice for use in this style.
Informal Upright Bonsai
The informal upright or moyogi bonsai style has a trunk that curves upwards in a series of “S” shapes. Again the branches of the tree are evenly spaced around the tree trunk, but the vertical distance between each layer of branches reduces as the observer’s eye moves up the tree. This effect is often enhanced by making the curves occur more frequently and tightly as the tree height increases.
The cascade or kengai bonsai style represents a tree growing on the face of a cliff. Classical rules dictate that the trunk of the tree rises to some foliage then the trunk tilts over so that it falls below the base of the pot, so that the lowest point of the tree lies below the base of its trunk.
The semi-cascade or han-kengai bonsai style exhibits similar principles to the cascade style, except that in this instance the trunk of the tree falls below the level of the rim of the pot but not its base. While the rules for the cascade and semi-cascade sound restricting, they are popular styles for bonsai practitioners and produce a tremendous variety of exquisite bonsai trees.
The slanting or shakan bonsai style takes the form of a bonsai tree with a slanting trunk, sometimes at quite a steep angle, which usually slants to the left or right when presented to the observer. While the trunk can be straight or curved, this style still observes the classical principles of gently tapering and having its branches evenly spaced around the trunk of the tree.
The broom or hokidachi bonsai style has a vertical straight trunk with all its branches pointing outwards to create a bushy, dome-shaped foliage similar to an inverted broom. Of all the bonsai styles, this most resembles a common tree shape. The branches are again evenly spaced around the trunk. The zelkova tree was one of the original species to which this style was applied, but elm and birch trees are popular for use in this style.
Non-classical bonsai styles tend to be look less structured initially to the Western eye but actually often involve some very difficult techniques and considerable expertise to achieve the best results. Many of the non-classical styles or combinations of styles can be used for a wide range of bonsai tree species.