ONE ~To the Radiant Season~ (or One: Kagayaku Kisetsu e) is a 1998 visual novel, by Tactics, a branch of the Visual Arts company Nexton. The makers of ONE ~To the Radiant Season~ would later form Key Visual Arts and make Kanon, they would however take alot of inspiration from ONE, especially character design. Take a look at the picture and then look at Ayu from Kanon.ONE tells the story of Kouhei Orihara, a Japanese high school student who suddenly finds his ordinary, everyday life pushed to the brink of collapse by the seemingly inexplorable expansion of an inner reality which threatens to replace his own. In the long and cold winter before the Radiant Season, he will encounter new friends, rediscover old promises, witness ties forged and broken, and learn of the things which everyone must leave behind.Kouhei suspects that at some point his current life will change while living a peaceful daily routine. His parents died when he was very young, and after his younger sister dies, he begins to seclude himself in the Eternal World, a world within his mind. The game's recurring theme is a focus on the Eternal World, an alternate space that Kouhei created out of his want for a place in which nothing ever changes. He starts receding into this world about a week before disappearing, during which every one (including the girl he loves) forgets about him, and he falls into the Eternal World completely, making it seem as if he never existed in the real world. His only hope of returning is to form a strong bond with someone prior to leaving, and to follow his guide back to the real world.The characters from ONE also cameo in the fighting game Eternal Fighter Zero by Twilight Frontier.
Cerebus Retcon: Misaki decides to take her revenge on Kouhei for running into her by saying "Who are you?" when he walks up to the roof, little did she know that he was in the middle of a breakdown because he actually was being forgotten by everyone, and she was the last one that would remember him.
Easy Amnesia:As you near the end of the game, everyone who once knew Kouhei slowly starts forgetting him until only the girl you chose remembers him (or alternatively, no one, if you didn't manage to get on a route) at which point he disappears.
After Kouhei disappears, but the game is told from the chosen girl's point of view until he comes back a year later.
Akane is also waiting for her childhood friend to return.
Gay Option: Subverted, though at times Hikami may seem like, he really just thinks of Kouhei as a close friend. Though he does (as a joke) say that if Kouhei wanted to try it with him, he wouldn't object.
Mythology Gag: If you look in the shopping district in ONE, you can see a sign that says rorikon (as in lolicon). Key would go on to make Kanon, which also has a "lolicon" shop in the shopping district.
Laser-Guided Amnesia: Toward the end, everyone forgets only Kouhei; no other memories are lost, the ones involving Kouhei are appended to exclude him.
This also happened to the friend Akane was waiting for and Hikami (where only Kouhei remembers him).
Late for School: Kouhei and Nagamori have to sprint to class regularely to avoid being late because of Kouhei's antics when getting up. Nagamori and Kouhei running to school is also the first CG the player sees in-game.
In Nasane's route, she takes over Nagamori's role as his personal alarm clock and the goal is to be on time within three days.
Lolicon: Technically Kouhei, in Mio's and Shiina's routes.
Moment Killer: A combination of situations 3 & 4 occurs during Nanase's H-Scene, Nanase is too nervous to go through with it, so just when it seems they are about to start, She clicks on the television and blurts out "OH LOOK SUMO WRESTLING IS ON, I LOVE SUMO WRESTLING." Kouhei just sighs and tries to steer thing back on course.
Near-Rape Experience: Kouhei plans to have Nagamori raped by an anonymous person but decides that this is a bad idea. This is the good route
Never Gets Drunk: Akane can hold her alcohol like a pro, even though she isn't even old enough to be drinking. She goes even farther by not passing out, remaining completely level-headed, and even cleaning the entire house.
New Transfer Student: Nanase turns out to be one, and Shiina also transfers schools if you take her route.
Not a Morning Person: Kouhei, who needs to be woken up by Nagamori at the start and (depending on the route) an alarm clock, Nasane or trains himself to do it.
Oblivious to Love: Kouhei during Nanase's route, he can't understand why she is disappointed when he takes her to cheap Ramen restaurant to try this new ramen on Christmas eve. He does eventually get it when she runs out crying.