To enable bonsai artists to guide and discuss their work, over a period of time, some arbitrary divisions, apart from the basic styles have been created. These can be called advanced styles and do not adapt themselves into the basic styles of chokkan(formal upright), shakan (informal upright) or kengai (cascade).
Three such advanced styles are the Fukinagashi (Windswept), the Bunjin (Literati) and the Bankan (Twisted).
As in other bonsai work, the Fukinagashi (Windswept) style too is an attempt at presenting a natural windswept effect in miniature.
The total effect is to give a bent effect that would imply growth slanting in one direction as though influenced by a strong unidirectional force of wind. The branches too would show growth in the same direction as the trunk.
In nature too, such growths of full-grown trees of the fukinagashi style, can be seen in areas subject to such unidirectional forces such as cliffs or hills. Though not quite the same, meandering rivers too are formed by natural forces of gravity instead of wind.
Technically, such forces cannot be created by bonsai artists, but the artist attempts, by other means to copy the effect without perhaps being aware of why such growth takes place.
Exerting pressure in a chosen direction, a living plant tends to grow in that direction. These physical stresses, not chemical stresses of unhealthy conditions, can be obtained by well-established techniques, developed over centuries.
Fukinagashi, or the windswept style, can be obtained by methods used to obtain the kengai (cascade) effect. While wires are used to train the branches, the trunk is usually shaped by harnessing it to an adjoining stake.
The effect is to present a sparse foliage just as in the natural version, where strong winds would have blown away the foliage while giving a bent shape.
It is opined that the Bankan (Twisted) style has come down from penjing, the Chinese art that was the forerunner to the bonsai of Japan.
As implied in the name, animal shapes particularly the dragon, are formed in the process of twisting and gnarling the trunk, in the bankan style.
Some sub styles such as the nejikan and takzukuri (octopus) are formed too. In the former, the trunk just makes a partial turn while in the latter, the trunk is twisted fully, and the branches too follow the pattern. These shapes emulate natural formations of full-grown trees of a vortex kind shaped by winds naturally.
Among the most popular of the bonsai styles, the Bunjin(Literati) creates a sparse but dramatic effect. Deceptively simple, yet difficult to achieve, it presents a slanted trunk with just a few branches. This style is thought to have been inspired by Chinese paintings of trees growing in harsh climes.
While Japanese Red Pines are popular, other varieties too are used for this style. The over all effect is to present a twisted trunk with branches angling sharply upwards. Branches too present twisted shapes as they rise. This presents differing views from different angles.
Every bonsai artist would want to create these advanced styles, but these are not for novices. Requiring great patience and skill, the rewards outweigh the effort that goes into creating these styles.