It is used in Sanshuko, that has two fewer scents than Genjiko and one less scent than Keizuko, and expressed by linking the heads of the longitudinal lines that seem to be the same scents with horizontal line, which rule is similar to the Genjiko and Keizuko.
源氏香より2つ、系図香より1つ香数の少ない三種香に利用され、源氏香、系図香と同様に、同香の頭をつなぐことで完成する。