Graham Potter using a trunk splitter to tear into a large branch stump. It’s from a video on styling an old larch (one of Graham’s excellent videos) on his Kaizen Bonsai site.
Why split?
Did you know that you can bend thick trunks by splitting them (in half, in thirds, in fourths, etc)? After splitting and bending, you can tie the pieces back together (just the way they were) and, if you do it right, they’ll fuse back into the single trunk you started with (with its new shape, of course). For a detailed description of this process, see page 77 of The Secret Techniques of Bonsai.
Do you use one?
Not many people use trunk splitters (they come in smaller and larger sizes), which is too bad. Not only do they split trunks, but they can be quite useful when carving deadwood (see above). Anything you’d like to add?