This is a compilation book of the original manga series "Yinka-chan, whose Yin level is gradually decreasing", which was conducted on Twitter and other platforms and posted every day for 20 days.The story is about a university student girl, Tsubame Takashi, who has no presence, meets a boy, Taisei Kyogoku, and tries to overcome her negative attitude little by little.It also includes a newly drawn manga that has not been published on the web.The story also focuses on the depiction of tights, so if you have a tights fetish, please pick up a copy!