- Touhou has innumerable doujins/fanfics detailing the Back Story of the characters, since not many characters have one to begin with, and even if they do, it's still pretty vague. By far the two most common recipients are Rumia (so popular that any fan referring to "EX-Rumia" is immediately understood) and Sakuya (serial killer, former monster hunter (Belmont lineage optional), or Lunarian being the three main theories). Touhou Tonari and Though the Wind Cries are good examples of this.
- Explaining what happened to the PC-98 characters, especially Mima, is widespread in the fandom.
- Detailing the future of characters is common, as amongst the incredibly long-lived youkai there are a few humans that will die relatively soon. Reimu, Marisa, and especially Sakuya (again) are the targets, though Sanae became increasingly popular after her arrival.
- The "Outsider Fic" subgenre, where somebody (often an Author Avatar, but may also be any kind of original character) somehow ends up within Gensokyo, either by accidentally/purposefully slipping through the Hakurei border (which, according to canon, is common), or by Yukari (in a sub-subgenre increasingly known as "Gappy Fics"). As a result, Fish out of Water antics ensue as they get acquainted with this Fantasy Kitchen Sink, and the outsider must either learn to live in this new land or find a way back home. Occasionally, they'll arrive just as an incident begins and they're forced to take part in it for one reason or another, teaming up with the canon characters. A fine example of this is ChibiChen's Mind The Gap.
- There is the So Bad, It's Good subgenre of "Gappy Stu Fics," wherein an Author Avatar is gapped into Gensokyo by Yukari, makes friends with several of the residents, becomes super strong after training with Reimu and Marisa, and beats up a bad guy in one of the worst incidents to ever hit Gensokyo. These fics start hundreds of subplots due to Loads and Loads of Characters, but never answer them before the readers just give up. This subgenre was taken apart by Diamond in the Rough (Touhou), showing the shallowness of these self-insert characters while addressing how dangerous Gensokyo can really be.
- Several doujins have Sumireko meeting with Sanae, who is overjoyed at meeting a fellow high-school-aged girl like herself (sometimes with the technology gap between the 80s/90s vs 10s showing up).
- The (mis)adventures of Team 9, an entirely fan-made Cast Herd consisting of child-like "low level" youkai (Cirno, Daiyousei, Rumia and Mystia), seems to be required for every significant story, even if only as a background detail. Indeed, the Non Indicative First Chapter of Imperfect Metamorphosis, and ultimately the entire story, is based around them.
- "One or more characters get turned into children" is an oddly common plot.
- Since the setting already relies on a system of formal duels to settle disputes, a common Excuse Plot (particularly for fangames) is "Yukari got bored and changed the system, so now the duels take the form of mahjong/soccer/etc.". This in turn actually is the basis of Touhou Soccer.
- The four great Fandom-Specific Explanations of Touhou are summed up by a well-known meme, namely this doujin panel◊. (Which has actually been altered from the original, which just had the first three lines.) Plus one more memetic response.
- Magic: Magic in Touhou is not overly defined, so it can be used to justify whatever needs to be justified.
- Eirin's shady new drug: Eirin's tendency to make unusual concoctions of dubious pharmaceutical benefit and bizarre effect is often used to justify strange happenings. Inaba of the Moon and Inaba of the Earth, generally considered canon, uses this one. And then becomes an irrefutably Ascended Meme when Legacy of Lunatic Kingdom uses this as a game mechanic. note Bonus points for Eirin sending out Reisen to deliver the medicine to Reimu, Marisa, and Sanae and convince them to drink it prior to the start of the story. note
- Yukari is fooling around again: Yukari is extremely powerful, extremely lazy, and extremely capricious; the plots just write themselves.
- It's a Moriya Shrine conspiracy: After their introduction in Mountain of Faith, the next three "main" games in the series (Subterranean Animism, Unidentified Fantastic Object, and Ten Desires) were either directly or indirectly caused by the Moriya trio's (more specifically Kanako's) attempts to gather more faith from the population. Suffice to say, fanon took it and ran with it.
- Templates like that are forbidden: Marisa says this in response to the above list. In more comedic stories, this has occasionally been used as an actual excuse for the plot.
Fandom Specific Plot / Touhou