Tokusa 木賊 / 十草
Horsetail plant motif. 木賊 is the plant; 十草 is commonly used for the tableware pattern.
Tokusa is a pattern of evenly spaced vertical stripes, named after the tokusa (scouring rush / horsetail) plant whose straight, segmented stems it evokes. Its simple, upright lines suit a wide range of tableware.
The tokusa pattern appears painted in blue on white porcelain, or delicately along the edges of vessels. On plates, the lines may extend from the center in a petal-like design.