I called it split trunk, maybe it is not what you call a split trunk. I got this at Brussels in 2012 in a nursery pot. Cut the top, cut the roots back, remove some of the soil but left most close to trunk, put in a bonsai pot to figure what I want to do. It did well in the pot, filled up with roots to the top. Last year 2013 it needed repotting, I ran out of time and did not get it swapped. It did well for the second summer on the stand next to the wall, full sun untill about 1pm. After that it is shaded by the house, I have found this works well for my shimpaku (killed a couple in the process of finding the best place). You can see the black dirt that needs to be removed and the large rocks are there to deflect the rain as it comes off the roof. I have really enjoyed the deep green color year around but know it needs light to the inside. I know the foliage inside will die if I do not get it open up to allow some light in, will it cause more damage? I still do not know how I want to do this tree, I do not want to end up with some pom poms at the end a the branches. I have a couple of ideas, but am open to any suggestions. I took more pictures but it is hard to tell much from them. I did remove all the soil and wash the roots this time. Put some wire on a couple of limbs to pull them down to let light in. Few more pictures in the next reply.