Root-Over-Rock – Sekijoju :
In this style the rock is at the base of the trunk, with the roots exposed to varying degrees as they traverse the rock and then descend into the soil below. This style takes time to develop, the roots of the tree must be growing on the rock long enough to grip and callus to swell and give the appearance of age. This style allows us to create an image that we see quite often in nature, allowing us to really attract the viewer to our image.
-Advantages of Root-Over Rock are that not only are you displaying a Bonsai but also an image of landscape. The roots flowing down throughout the rock give an impression of age and struggle. Bonsai that seem as if they are taken right out of their natural landscape and put into a pot are some of the most appealing images, and Sekikoku allows us to convey that image.
-Disadvantage of Sekijoju is the ability to find a rock that really matches the image you are trying to convey. A lot of times people choose rocks that are far too small for the final image they are creating. I have seen many trees that the roots have almost completely engulfed the rock and it looks a little strange. The key is to pick a rock much larger then you would really think, allowing the tree to grow into the image over time. Remember we are thinking 10-20 years down the line with our bonsai.
All types of trees can be applied to this style.
Trident Maple (Acer Buergerianum)