Also called *kaiga 界画. A line drawing technique where a straight edge or drafting tool is employed as an aid in drawing precise, straight lines for architectural structures and furniture. These lines are usually drawn by holding two brushes together, one upside down, and then running the tip of this brush along a groove in the ruler while drawing the line with the inked brush. The technique is also called mizobiki 溝引き (pulling along a groove). A trained hand can vary the pressure on the brush to produce thick or thin lines. Parallel lines are produced by slightly moving the position of the straight edge. In Japan, fine examples of this technique may be seen in handscrolls from the Kamakura period. In China, the early Northern Song painter Guo Zhongshu 郭忠恕 is famous for his use of the technique.