Bonsai styles

Bonsai is a Japanese art form using miniature trees grown in containers. Similar practices exist in other cultures, including the Chinese tradition of penjing from which the art originated, and the miniature living landscapes of Vietnamese hòn non bộ, but this article describes the Japanese tradition.
The Japanese art of bonsai dates back over a thousand years, and has evolved its own unique aesthetics and terminology. A key design practice in bonsai is a set of commonly understood, named styles that describe canonical tree and setting designs. These well-known styles provide a convenient shorthand means for communicating about existing bonsai and for designing new ones.
Styles can be grouped based on different criteria, such as the trunk orientation or the number of trunks in the bonsai specimen. Some of the major style groupings include:
These terms are not mutually exclusive, and a single bonsai specimen can exhibit more than one style characteristic. When a bonsai specimen falls into multiple style categories, the common practice is to describe it by the dominant or most striking characteristic. For example, an informal upright tree with prominent areas of missing bark and trunk scarring will be described as a sharimiki rather than a moyogi.
The system of styles serves many purposes, some practical, some aesthetic. In their simplest and most common application, styles provide a form of shorthand description for bonsai specimens. The brief style term appears in catalog descriptions, usually with a species identifier, and thereby compactly describes the subject bonsai. Style names can also be used to group comparable specimens in bonsai viewing and competition. Even considering the styles simply as descriptive labels, the system still simplifies bonsai teaching and learning, and provides widely understood terms for public communications about bonsai.
Predefined styles also aid the designer in making a development plan for a pre-bonsai tree. The untrained specimen may have characteristics that suggest or rule out certain styles. For example, a crooked trunk makes a tree unsuitable for the formal upright style, and suggests to the designer that the tree may be trained better as an informal upright or a slanted style instead. A damaged or highly asymmetrical tree may not appear suitable for bonsai development, yet may be adapted to an uncommon style like windswept or raft, which both work for trees that have branches only on one side of the trunk. Some tree species are not suitable for some styles: a bonsai artist working with a deciduous tree will not produce bonsai in the cascade style, for example. The designer can evaluate the pre-bonsai specimen against the catalog of accepted styles to determine what branches to remove or reshape, what foliage to remove or encourage, and what detailed shaping to apply to trunk and branches.
Although the styles will guide a bonsai designer, they are not completely deterministic. A review of actual bonsai from competition catalogs will reveal that even highly regarded specimens rarely meet every rule laid out for their style. The species of the bonsai, the age of the tree when it began bonsai training, the tree's pre-existing shape and structure, even the bonsai artist's training and preferences, strongly affect the shape of the resulting bonsai. These competing influences ensure that the style system acts mostly as a creative aid, not a dominating constraint, in producing a finished bonsai.