white deadnettle (Lamium album var. barbatum)
A variety of white deadnettle native to Japan. The name literally means 'dancing child grass', from the flower's resemblance to a dancing figure.
In spring, you can see white deadnettle blooming along the roadside.
Kanji spelling is rare; the plant is usually written in kana.
Variant kanji spelling; even rarer than 踊り子草.
From 踊り子 (odori-ko, 'dancer') + 草 (sō, 'grass, plant'), referring to the flower's shape resembling a dancing figure. The exact historical derivation is uncertain.