Formal Upright | Informal Upright | Slanting Style | Cascade | Semi-Cascade
In nature, such trees bend or alter their direction away from wind or shade other trees or buildings, or towards light. In an informal upright bonsai the trunk should slightly bend to the right or left - but never towards the viewer. (This applies to all types of bonsai. Neither the trunk or branches should be pointing towards the viewer when the bonsai is viewed from the front.)
Recommended Species: Most species of plants are suitable for this style, mainly the Japanese Maple (Acer palmatum), Trident Maple (Acer buergerianum), Beech, practically all Conifers and other ornamental trees such as the Crab Apple, Cotoneaster and Pomegranate.
Processes/Techniques Used: An informal upright bonsai basically uses the same principles of the formal upright bonsai only that it is informal. 
The style still requires a tapered trunk, however the trunk direction and branch positioning is more informal and closer to the way a tree would look when exposed to the elements at an early age. The trunk usually takes on an unexpected curve or series of twists and the branches are thus positioned to balance this effect. As with formal upright, the crown of the tree is mainly very full with foliage and despite the informal trunk, is most always located directly above the base of the tree. (This is an attribute of the informal upright style, if not done like this, the tree would be slanting.)
Jin (carved remains of dead or unwanted branches to look like dead and rotting limbs of a tree) is also more appropriate and effective with the informal upright style.