Before carving the bark, more fine detail is given to the knot in the trunk, which also serves as the wood spirit portal. Because it lies on the outer surface of the trunk, the cuts cannot be too deep. Special undercutting techniques are used to create the shadows and give an illusion of depth well beyond the actual depth of the cut. This requires precision use of micro carving tools and extraordinary patience. Many shallow strokes are necessary to carve the shape and deepen the lines.