Shari is one of the dead wood built for bonsai and it can greatly improve the landscaping value for the whole plant. Normally there are two types of dead wood specially created for bonsai plants, namely, jin and shari. Shari means the trunk without barks and jin indicates small barkless branches.
For normal trees in the real world, some external damages will cause some types of dead wood such as the heat, coldness, winds and lighting. The dead wood technique is usually used for evergreen trees instead of the deciduous since the one on deciduous will rot off quickly and hard to preserve. The best time to build up shari or jin is in spring or autumn when the temperature is not too hot or cold. You should do some practice beforehand if your target tree is not a cheap one. Some tools such as jin pliers should be used to help you do the work.
The first step to create the shari is to choose the correct location for the cutting. You should pay some attention on this cut because you may accidentally cut the vein for the nutrient transport, resulting in the tree being killed. You should remove the bark from the trunk and do some shaping work afterwards. If you are not sure about your expertise for creating the shari, you can slow down the process into several months. You can use jin piers to peel off the bark and then use some concave cutters to hollow out the trunk. The last step should be the bleaching and you can use some Lime sulfur to help it resist the infections.
Image provided By Ingeborg Bernhard (Schnobby) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons