The seventh 節気 “sekki” division of the traditional Japanese calendar is:
立夏
(りっか)
“rikka”
‘beginning of summer’ // ‘first day of summer’ (solar term)
The second “kō” microseason within this division is:
蚯蚓出
(みみず いずる)
“mimizu izuru”
Worms surface
That makes 蚯蚓出 the twentieth microseason of the year!
It typically lasts 10~14 May.
Click here to learn about this subseries
Image credit: “Song Thrush Waiting for Worms” – original author unclear.