“Kourin” (香霖(こーりん), Kōrin) is the canonical nickname for Rinnosuke Morichika, an antique store owner from Touhou Project. It had a small history in the Japanese fanbase as he was a relatively unknown character until the 2010 anthology,¹⁾ so the fans came up with a lot of warped interpretations.

In the first chapter of Touhou Kourindou, we have Marisa using 'Kourin' as a nickname for Rinnosuke, and the Japanese fanbase followed suit as Rinnosuke's actual name contains archaic kanji²⁾ that Japanese IMEs wouldn't normally suggest unless you knew how to configure it. As a result, most Japanese discussions about Rinnosuke would occasionally borrow the 'Kourin' nickname to get around the issue and it stuck.

“Perverted Kourin” (変態こーりん, Hentai Kōrin), or “Mannosuke”,³⁾ was a fan interpretation of Rinnosuke Morichika which mischaracterized him as a bizarre, muscular, loincloth-wearing gag character that had short-sighted perverted tendencies (e.g. voyeurism) since people wanted to poke fun at the idea of him being the only male, at the time, in a majority female setting.

The idea stems from the 2nd Touhou Saimoe Tournament, where an illustration of this half-naked, muscular Rinnosuke was uploaded for the Rinnosuke–Reisen match on February 1, 2005.⁴⁾ Rinnosuke lost, but the iconic illustration would end up warping people's perception of him. Eventually, these cheap jokes grew stale, especially after the 2010 anthology, and sorta faded since there wasn't really a demand for it.

• Cookie☆☆ S1 - One of the late depictions. Remember that the original did not have visuals.

• Kourin + Perverted Kourin on Pixiv Encyclopedia
• Kourin on Niconico Encyclopedia

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