Just wanted to add something so that people who have just started or have not been doing bonsai very long are not confused about what is being said here.....Any tree that is given a good root pruning and repotted must be tied into the pot... A newly root pruned or heavilly root pruned tree does not have much of a base, it tips and wobbles. You will never get a moderately or greater, root pruned tree to sit where you need it to on it's own. When a tree is repotted, sometimes it needs a tilt or a turn etc...and in order to make it sit and stay... The tree needs to be tied... This is not an opinion, but just the mechanics of it.. If something has had much of it's base removed, it is unstable....No, if you have a root bound tree and you remove the tree and put it in another pot, it will not move. However, if the tree is in that shape, it should be root pruned anyway...
rob