This was my first big Bonsai at the start it was 550mm high with a 55mm trunk after 10 years of training and nurturing it is currently 850mm high with a a 120mm base , while it does look fantastic i have yet to stimulate good surface roots or "Nebari". I have began to work on the root system to improve the radial surface roots by removing and peeling back numerous small sections of the bark , painting these areas with hormone gel and using a cut off split plastic pot or a terracotta split pot to raise the course, sharp mixture around the base of the tree. A small open wooden box will do they same job , i use whatever i can lay my hands on . You could remove the Bonsai from its pot and place it in a deep plastic pot , either way will produce the desired result. Due to the fact the soil level has been raised the top section will dry out before the pot so keeping a close eye on the top section is a must. The lower branch on the tree is only 5 years old grown from a shoot during development of the canopy , numerous shoots appeared in that year and i chose the best one to balance the tree . I allow the branch to grow on moreso than the rest of the branches to thicken and improve ramafication , however it is always in proportion to the rest of the canopy . Originally this tree was part of my landscaped yard until a motorcyclist being pursued by the law took a shortcut through my yard and struck the top of the tree snapping it off. At the time i was rather angry , however the young chap done me a favour as the root system on the tree would have managed to foul the drainage system on the house.