First the tree was taken out of the container. The soil was hard like cement. It seemed not to have been repotted really for a few decades. Often with such trees folks don't dare to disturb the root ball and juust take the tree out of the container, clean a bit and put it back. This is not repotting though. Well, the spurce seems to be quite healthy despite. As one can see I had to use a reciprocating saw to get it out. This is normal professional procedure on such trees. Then you can see that the root ball was cut around. Which is what should be done at repotting.
The strange root was uncovered.
I happen to have had a stone slab that was the perfect fit. It is a natural stone coming from Germany.
The tree was placed on the slab to see how it fitted. Then I took off a few parts underneath to fit right into the natural shape of the stone. See my head for size comparison.
The strong lowest branch, the main branch was cut off and replaced by a rather unassuming jin. Then a thick branch on the upper third right was taken off too. Now the tree all of a sudden has a strong movement to the left, while it had one to the right before. The strong root on the left told me that the crown should move to the left too. And then the whole crown was way too wide and just too nice for an old tree. Now it is much more compact.