Iyo Meito, originally known as Yoshu Iyoto, is a natural whetstone with a history of 1,300 years. At the time, white whetstones were considered the highest quality Iyo whetstones. Princess Miotsukushi called the white whetstones "Koume" (small plum), "Hakubai" (white plum), and "Murasaki" (clouds) based on their appearance.

Among white whetstones, "Hakubai" has a warm orange hue, and its moderately hard and smooth clay creates a delicate sharpening feel.