7TC7 had posted it a few pages ago, the hat shape looks like a jiangshi. Maybe Yoshika got enough flexibility training from Seiga.
It's not,
it's apparently a conical hat with a big visor (that would make it a cap, then) or with a squared brim in its periphery. It's not possible to tell which one, but by looking at how it moves (cfr. the gif quoted a few post above), it has an external located volume and doesn't have like a spontaneously broken symmetry form. I first thought the same though, but we need to look carefully.
(For Yoshika, if my memory is still good, you will anyway never ever see her with a traditional jiang-shi hat, so the question would not arise. ZUN originally wanted to make yoshika with a traditional jiang-shi hat (which is relatively normal for a jiang-shi), but didn't want people to think it was copied on some other famous jiang-shi characters (like hsien-ko) and he changed the design of the hat because of that. I don't know where I heard/read this story though, maybe someone can confirm it's true or not.)Talking about that silhouette, here is a small update of what she could possibly look like (according to the exact shape of the silhouette):
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(and here is one for
Tengukami if he was right.... '-' )
Two thoughts...
1-Would Yuugi fit in with the game's motif given her stated ability is "Wielding unexplainable phenomena"?
2-Mima is kinda the ultimate urban legend of Touhou fandom, isn't she?
I would love to see Yuugi in the game,
she's amongst my 8 favourite chars (well, Kasen is here and she's
potentially an oni too), but I don't think it will happen... Also, her abilities is due to the fact she's an oni, if you search all the "weird and unexplained phenomena", you could think about almost all the characters since a lot of them are Youkais (that comes from folklore or (urban or not) legends).
And I had the same reflexion for Mima being an "urban legend", but it's so meta to be considered, lol.