Kanji
If it means anything, there's a Yu-Gi-Oh Card that uses the kanji "浮幽" called "浮幽さくら" (fuyu sakura). For reference, the character on the card is a ghost girl with a scythe. A pun is made of it as "浮幽" (fuyu) is a homophone of the Japanese word for Winter, but the kanji used supposedly reads "Floating/Drifting Ghost". So it sounds like "Winter Cherry Blossoms" but actually says "Floating Ghost Cherry Blossoms". When the card was released in English it was written as "Ghost Reaper and Winter Cherries."
With this in mind, is it possible that there's a connection between this world's name and this random Yu-Gi-Oh card?. It may be possible that this world has a similar pun, with "fuyukai" being a homophone of the Japanese word for discomfort/unpleasentness.
I'm tired so sorry if this doesn't make much sense, but I'm trying to spark up some ideas of how we could work out this world's Japanese name.
Cola160 (talk) 09:28, January 4, 2018 (UTC)
Dunno if that's the intended reference, but that's interesting. It's pretty much the only partial match that comes up if you google it, not sure if that's coincidental though. The pun might be intentional, atleast.
Still, unsure about how to read it all together. For now, I guess the joke is "unpleasant ocean", haha. LainIwakura (talk) 10:08, January 4, 2018 (UTC)
I suppose we could make a footnote of this, or explain it in, say, the trivia section. Lips McGee (talk) 22:29, January 4, 2018 (UTC)
浮幽 is not read as fuyu (冬) though, so there's nothing wintery here. Instead it's fuyuu, with a long u, same as 富裕 (wealth, riches, opulence), 浮遊 (floating, wandering, suspension) and 蜉蝣 (mayfly, ephemerality (of human life)), even though the last one is usually read as kagerou. I think there might be a link with the second one, like, you're suspended (浮遊) in a dark, secluded (幽) place... Skorokhodov (talk) 11:07, January 5, 2018 (UTC)
From what I've heard, 幽 can actually be pronounced as just "yu"; in fact, the Touhou character, 幽々子, you'd think her name in English would be Yuuyuuko, but it's actually just Yuyuko; there isn't even any dispute of this. I'm not sure if the name falls into some grammatical pothole which forces it to remove the extended vowel, but if the Touhou fandom, and apparently even ZUN himself, are all so certain that it's "Yuyuko", then there's a decent possibility that it really is meant to just be "Fuyukai".
That said, I'm not sure. Admittedly, the pun could even include this discrepency, including both "winter" and "suspension", making it officially the most layers to any pun I've ever read.
EDIT: Technically her name is 幽々子, but the 々 means a repeat of the kanji before it, so it's the same as 幽幽子. Lips McGee (talk) 17:46, January 5, 2018 (UTC)
I intended it as ū, just didn't bother to think about writing it as "uu". The question is what 幽 is meant to mean in this context since it can mean a bunch of things. But yeah, it might just be fine as secluded, like "floating in a quiet secluded place". The unpleasant ocean pun is pretty good though.
It's also possible to make the same kind of pun Cola mentioned, considering the second half sounds like yūkai, ie the underworld / ghosts. LainIwakura (talk) 23:28, January 5, 2018 (UTC)