"Do you know the title of this song? It's Canon. Pachelbel's Canon. It repeats the same melody and crescendos gradually, peacefully, and beautifully. It would be nice if life changed like that: slowly but surely, while being seemingly unchanged from day to day."
Kanon is a well-known eroge with a clean version, as well as many, many adaptations. Despite its Multiple Demographic Appeal to girls, it's actually a seinen series. Besides the Visual Novel, there are two anime adaptations (the original Toei one and the new Kyoto Animation one), CD dramas, a manga, a series of light novels, an Alternate Continuity manga called Kanon Another Story: Wonder Three, and a non-canonical gag manga crossing over with AIR. The original game was never released outside of Japan, but a completed English translation patch presently exists courtesy of Non-Directional Translations.Ordinary High School Student Aizawa Yuuichi used to visit his aunt Minase Akiko and cousin Nayuki in their quiet little town every holiday, but one year something happened and he left for seven years. When he transfers to Nayuki's high school, his memories of that time remain a blur.Upon his return he encounters a number of mysterious girls from his past who all need his help. Bokukko taiyaki-thief Ayu searches for a precious lost item she cannot describe. Quiet and serious Mai hunts demons in the school after dark. The childish tsundere Makoto suffers from amnesia and has no place to go. The sickly Shiori is estranged from her sister and never present at school. Finally, there's the lonely Nayuki, weighed down by rejection and tragedy.Yuuichi resolves to help them, but as he gets involved, he discovers that there is far more to the girls than meets the eye. Mystical happenings lie hidden in this strange town, tied to Yuuichi's forgotten past. In dealing with the girls, Yuuichi must face his lost memories. What happened seven years ago, and why can't he remember?Absolutely not to be confused with this Kanon, a shoujo manga by Chiho Saito, or K-On. Or the trope Canon.Character Page under construction here:This franchise provides examples of:
Absurdly Sharp Blade: Mai's sword. While it wasn't a clean cut, she still breaks a brick wall with it. (Also, when thrown, the sword tends to sink deep into floors, walls, tables, as if they were made of half-melted butter.)
Yet strangely averted, as it can't even cut a banana. It doesn't affect how it hurts demons, so Mai doesn't really care, but it seems to contradict how the sword sunk into the floor during one of the earlier battles.
Aloof Dark Haired Girl: Mai is very quiet, inexpressive and difficult to read. Unfortunately, this just leads to her weirding people out.
The Artifact: Being one of the first visual novels, the game incorporates a calendar system from the older type of "micromanagement hell" dating sims. Everything happens sequentially rather than on any specific date, however.
Childhood Memory Demolition Team: Twisted. Both demolitions (the barley field and the tree) were done right after Yuuichi left town as a child, so he barely had those memories when he returned, and he didn't really want to remember the tree, either.
Clap Your Hands If You Believe: The comatose Ayu still believed enough in her promise to Yuuichi and the wishes that she made on a simple crane machine doll that she was able to spiritually project herself as a solid living being even seven years later.
Cutting Off the Branches: In the visual novel, there are five separate girls with five separate storylines, but Yuuichi/the player is only meant to experience one arc. Playing out the other girls' storylines requires playing the game again. The anime adaptation, however, has four of the five arcs happen sequentially. This results in some confusing characterization. For example:
Yuuichi develops a close bond with Makoto. She dies and he's upset, but by the next episode, he's back to normal. He has another intense experience with Mai, but once her plot from the visual novel is complete, Mai no longer appears in the show, even though she's presumably still alive and in town. Yuuichi neither mentions nor visits her. Shiori receives the same treatment as Mai; after her arc, she is not mentioned and no longer appears, even though Yuuichi has formed a close friendship with her.
Once the previous girl's arc has been completed, some of the supporting characters of the previous arc (Amano for Makoto, Sayuri for Mai) also disappear from the show, without any exit for the characters.
This is all a product of making separate plotlines take place one after the other. The visual novel ends once it reaches a conclusion for one of the girls, and each alternate arc is a replay. For each new arc, Yuuichi is largely written as though he never experienced the previous arc and never bonded with those missing characters. In a replay of a visual novel, where each arc is a separate continuity, this makes sense. In the anime, where each new arc takes place after the previous arc, it's awkward and jarring.
There's some attempt to patch this: in Episode 23, Yuuichi finally mentions the previous three girls and cries, but it makes little sense that Yuuichi is only upset about them now and didn't spend any more time with the two who were still alive. In Episode 24, all the missing characters return, but their absences remain unexplained.
Dub-Induced Plot Hole: Yuuichi's breakdown when talking to Makoto (the real one) near the end of the 2006 anime has him accidentally say "when I was seven" instead of "seven years ago" in the dub. Kanon may have Suspiciously Vague Age going on, but it's clear from context that Yuuichi is seventeen, not fourteen.
Foreshadowing: A veritable masterclass. Just how cleverly the dialogue is written - everything said has at least one other layer of significance — can only be fully appreciated on repeat viewings. The anime adds a little more.
Freeze Frame Bonus: For just a second in Episode 6, when Yuuichi and Ayu are in the cafe after going to the movies the adult Makoto can be seen walking by outside the cafe.
Also for just a fraction of a second Episode 14, when Yuuichi and Sayuri are in the cafe, you can see a scar on Sayuri's wrist, hinting at a suicide attempt (mentioned more explicitly in the game).
The Gadfly: Yuuichi, who enjoys annoying his love interests so much that it's nearly his defining character trait.
Gargle Blaster: Akiko's "Special Jam" is so infamous that Yuuichi and Nayuki beat a hasty exit everytime somone is about to try it.
Generation Xerox: Akiko and her daughter Nayuki. Akiko sleeps less and runs less, but they look almost the same, have very similar personalities, and even crack the same jokes.
Generic Cuteness: The show is so heavily loaded with moe characters, it's just about impossible to guess which ones are intended to be attractive in-universe (Leads to Informed Attractiveness). That said, the non-speaking and one-or-two-line characters look even more generic — almost interchangeable — yet they're far less cute than the major characters.
Go Out with a Smile: Poor Makoto after her "wedding" with Yuuichi, making him possibly the youngest "widower" in romantic anime.
Gratuitous German / Foreign Language Title: The title of the franchise is taken from Pachelbel's Canon (Kanon in D-dur), which figures periodically in the 2006 anime. Alas, the franchise gets the meaning of the word "canon" all wrong. The confusion derives from the fact that Pachelbel's Canon happens to be both a canon and a passacaglia (or a ground base, which is more or less the same thing). Passacaglia is the forerunner of the theme and variations, and that, rather than a canon, is the basic musical form the franchise is loosely organized around. Four of the five paths in the original Visual Novel have links both to Yuuichi's forgotten past seven years ago and his childhood promises from then, along with supernatural elements, and a girl who needs his help (and love). Each girl, and the path she represents, is a variation on a theme. By contrast, a canon need not have the structure of a theme and variations; it fact, it seldom does. Rather, a canon is a musical form defined by its use of exclusively strictly imitative counterpoint (in contradistinction to a fugue, which employs both strictly imitative and freely imitative counterpoint) — although said "strict imitation" can nevertheless run backward or upside-down or any of dozens of other complex tricks, so long as the pattern of intervals remains unchanged.
On the other hand, would anyone have played the Visual Novel or watched the anime if it had been burdened with a name like Passacaglia?
This trope is implied to be the third wish that Ayu wished for while in a coma, the miracle that managed to save everyone that Yuuichi cared about. Yuuichi discusses it at length with Shiori in the KyoAni anime.
Shiori: I don't know what exactly she wished for, but maybe, 'I want my dearest person to always be smiling'. Maybe it was a wish like that.
Jerkass: Kuze from the student council; even moreso in the original game than in the 2006 anime.
Jerkass Fašade: Kaori counts as this when Shiori is involved, especially in the anime.
Kidanova: Yuuichi's harem is established when he's ten. Which may be the universe's advance payment on the future tragedies that befall them.
Last Girl Wins: In the 2006 Kyoto Animation version, all of Yuuichi's important romantic options are introduced — or at least glimpsed — in the first episode. But the episode ends with Yuuichi and Ayu together. Ayu is also the First Girl, the Last Girl, and the closest thing to a protagonist in both the opening and closing credits. See also First Girl Wins.
Look Both Ways: Akiko is hit by an SUV, but survives thanks to Ayu's miracle.
That totally wasn't her fault, though, since the driver that hit her was apparently an idiot who can't tell the difference between red light and green light.
Trope relevant to anime only: In the Visual Novel, the driver lost control going around a curve, rather than not recognizing a traffic light. Akiko simply had the unfortunate luck to be on the sidewalk at the wrong place and time.
Magic Skirt: Mai when she jumps off the school building to defend Yuuichi from the "last demon"
Marth Debuted in Smash Bros.: The cast of the show first debuted in the West in the cameo in Air. It didn't take ADV too long to pick up the KyoAni version of Kanon, but the Toei version had been out for half a decade at that point.
Meet Cute: Yuuichi meets almost every available girl in an odd manner. To wit:
Ayu literally runs into Yuuichi before dragging him off with her, an irate taiyaki vendor in hot pursuit.
Shiori meets Yuuichi after Ayu faceplants into a tree and said tree drops its snow on her.
Makoto first appears punching Yuuichi for a slight he committed that neither of them can even recall.
Nayuki, the First Girl, is a tamer example of Meet Cute — but even she arrives two hours late to meet Yuuichi at the train station. Outside, on a bench. In a snowstorm. Of course, they already know each other, being first cousins. Then again, Yuuichi already knows most of the other girls from ten years earlier, anyway. But he's forgotten them.
Not So Weak: Mai. Obviously, she's a demon-killing badass in her own way, but she's also very selfless. Hell, she lets a dog try and eat her hand after it was attacking people because she had nothing to feed the thing. See also: Constant abuse from student council, other students and teachers.
Once an Episode: Ayu runs into Yuuichi. This doesn't, however, happen at the end of the arcs of all the other girls, but there's a reason for that.
Parental Abandonment: Ayu's father and stepmother are said to be out of town, and she can't reach them. Yuuichi's parents are out of the country, and Makoto's amnesiac and can't find her parents, if she has any.
Parental Substitute: Akiko. If you're homeless girl who needs a roof over her head and 3 square meals a day, just ask and you'll have an instant family of your own, no background check of your shady past needed. She goes as far as to say "Come play with Mommy" to Makoto as the latter begins to lose her memories.
Perfect Health: Shiori initially Hand Waves her skipping of classes and lack of energy as "a cold." While this excuse rapidly wears thin, the heartbreaking revelation is somewhat spoiled by the audience being well aware it could only be a fatal condition.
Pinky Swear: Yuuichi and Ayu's relationship is marked by several of these.
Pretty Freeloaders: Makoto starts out as a Pretty Freeloader before becoming an Unwanted Haremette. And Akiko, who is not one of the available girls but the Hot Shounen Mom, lets the girls have the run of the house and talks Yuuichi into helping them out when he doesn't want to; the only thing keeping her from qualifying is that she's the one that technically heads the house.
Snow Means Death: The 2006 version of Kanon has Yuuichi searching for Ayu in a raging blizzard, then giving up and waiting for death. There's also the Look Both Ways incident, which was made more dramatic with the scene of red mixed in the snow. And when Makoto dies, a previously completely green area was instantly covered in snow.
Swiss Army Tears: Deconstructed in one route. Mai Kawasumi cures her mother with her tears, and people eventually learn that her tears have the ability to rejuvenate anything, even after it has died. Unfortunately, since she's living in a modern setting, she gets swept up in a media circus that publicizes her powers, gets persecuted by the people around her for being different, and is eventually forced to leave her town.
Themed Harem: Childhood friends, with Shiori the odd one out.
There Are No Therapists: The girls' mental health thrives on Yuuichi helping them to discover their own strength, and just Yuuichi. Then again, a school nurse wouldn't help Mai if they had one because the administration hates her, Nayuki's main source of support, her mother Akiko, is hospitalized at the exact time that she needs her the most, Makoto's an animal in human form, Ayu's an astral projection, and Shiori isn't even supposed to be out.
Tomato Surprise: The true natures of both Makoto and the demons Mai is trying to kill are pretty big tomatoes by themselves, but the author pulls this twice in fairly-rapid succession with Ayu: 1) when Yuuichi first remembers her falling from the tree, and then 2) when Akiko tells him he's mistaken — she's not dead, just in a coma.
Tricksters: Yuuichi and Makoto bring this out in each other. Makoto nearly always gets the worse end of the deal; for all her effort, she's not all that skilled at trickery. Ironic, since she was actually a fox before a wish turned her into a human. (It's also quite likely she loses, at least in part, because she's in love with Yuuichi and what she really wants is to play with him, rather than actually defeat him. In fact, her whole reason for becoming human was to return to his side and spend time with him before her death.) See also Troll.
Troll: Yuuichi really seems to enjoy the reactions his snarky comments and strange explanations get. It helps that the girls are generally very gullible, but they start to catch on somewhat.
Verbal Tic: Ayu's "uguu", Makoto's "auu", Nayuki's "nyuu" when she's sleepy, Mai's "...", Sayuri's "hoe" and "ahaha".
Ayu's immaturity and repeated usage of the tic "uguu~" are all justified by the fact that she's basically still ten-year old Ayu Tsukimiya being projected by her comatose self.
What the Hell, Hero?: Some of the choices in the game lead Yuuichi to do some really nasty things to the girls that only serve to make him look like an utter asshole. One notable example being stomping Ayu's taiyaki bag into the snow.
Appropriately enough, Yuuichi gives Makoto a major one after she drops Piro off the bridge.
Willing Suspension of Disbelief: In the anime, since they have 5 characters to go through in 24 episodes which sums up around 3-5 episodes per girl, post deduction of the exposition; that means the plot for each arc / route has to advance quickly; which enforces Ass Pull characters or motives to appear without any explanation or proper legitimization to advance the plot. But the viewer is willing to avert one's gaze away specifically because of the limited number of episodes. The prime example of this would be the fact the protagonist goes one love interest after the other in such a short time.
Big Brother Attraction: Ayu calls Yuuichi "oniichan", despite their being the same age. This appears to be to shock readers used to an Ayu ending in every adaptation into realizing that, hey, this ain't the Kanon they're used to.
Establishing Character Moment: Everyone whose personality is markedly different gets one. Yuuichi starts a snark war with Nayuki that goes far past any other Yuuichi's limits to how rude he can be, and Nayuki is just as rude back. And Shiori? Shiori wraps a rock in her shawl, tosses it at Yuuichi and Kitagawa, and blames it on the wind.
I Have No Younger Sister: In this version, Nayuki actually knows from the start that Kaori and Shiori are sisters and says so even when Kaori's denying it to her face, which makes the relationship dynamics somewhat more messed up than usual.
Love Triangle: Nayuki insinuates that a Type 4 is going on between Sayuri, Mai, and Yuuichi. Whether Sayuri actually does love Mai is up for debate, but the mangaka probably knew the pairing's popularity.
Off Model: Say what you want about Key's own art style, but this takes getting used to.
Spoiled Sweet: Shiori; she even acts up-front about her illness instead of hiding it because she's used to people treating her better if they know she's dying, but she's still one of the nicest people around. (Okay, in a manga where Minase Nayuki is a complete jerk, "nicest" is relative...)