Bonds of Yachiyo is an Explorer Horror game in RPG Maker with H-Game content by Aoi Tsuyukasa and published by Saikey Studios, released in 2025. It has a work-safe version available on Steam with an 18+ patch on the publisher's website.

After a strange nightmare in which she found herself in a village chased by strange men with gaping holes for faces, university student Kusumi Chiyo wakes up from a nap and goes to class with her best and Only Friend since childhood, Akari. The two of them chat for a bit — but an earthquake knocks out the floor beneath them, plunging them into darkness. When they wake up, they've been separated and thrust into a version of their university that's old, dark, and filled with the monstrous humanoids from Chiyo's nightmare. Now Chiyo must navigate this other world and find Akari while discovering the history of the strange village from her nightmare, receiving help from a mysterious boy named Yakumo Kokonoe, and facing the Shrine Maiden of the Tied Rope who controls all in this dimension.

Gameplay is the typical explorer horror fare, with navigation and completing puzzles while evading monsters; however, getting caught by an enemy will raise Chiyo and Akari's Corruption meter, and the level of corruption will affect the available endings.

This game contains examples of:

• Big Bad: The Shrine Maiden of the Tied Rope is the master of the other world where Chiyo and Akari have been imprisoned, and wants to keep them from leaving so she can eliminate the other half of Akari and have Chiyo all to herself.
• The Blank: The main enemies the heroines encounter are ghastly humanoid beings with gaping holes and eyes where their faces should be. They can shapeshift into more proper humans with faces, however.
• Childhood Friend Romance: Chiyo and Akari have been friends since childhood, and when they end up separated by the other world, they eventually come to realize they see each other as more than friends, to the point of having a Relationship Upgrade in several endings. Also applies to their prior incarnations Yuki and Nao, who met as kids when Yuki was kept inside her manor’s storehouse and eventually tried (and failed) to run away together.
• Dead All Along: Akari, the Deuteragonist best friend of Chiyo, is revealed halfway through to be a spirit who has been attached to Chiyo her entire life; later we learn that she was killed as a Human Sacrifice by her home village.
• Doing In the Wizard: While there are supernatural activities going on in the plot, it turns out that the "curse" of illness and death afflicting the village that at least three shrine maidens were sacrificed to stop, in order to appease the Great Serpent, was actually just avalanches and toxic volcanic gas; unfortunately, that meant nothing was able to stop everyone from dying of the gas, or killing each other in anger when it seemed that the last ritual failed.
• Eerie Anatomy Model: One of them is in the first area and holds an item that you need to progress, and also serves as the first enemy that comes alive when you get the item from it.
• Five-Second Foreshadowing: At the end of Chapter 2, Yakumo calls out to Akari, leading Chiyo to express surprise that he can see her. In the subsequent Interlude, we learn that Akari is invisible to everyone but Chiyo due to being a spirit.
• Foreshadowing: At the end of Chapter 1, Chiyo comes across a shrine maiden who calls her by the name Yuki — the name of her prior incarnation.
• The Great Serpent: The god of the ancient village, who they performed Human Sacrifice to appease lest they incur his wrath and subsequent curse. However, it turns out to not actually exist but was misinterpreted from an ordinary avalanche, the "curse" really being toxic gas from a nearby volcano.
• Greater-Scope Villain: Lord Morimichi Tsukishiro, the head of the old village, and his followers are long dead, but caused the main plot by killing Yuki and Nao as sacrifices to their god, which resulted in them reincarnating as Chiyo and Akari as well as the creation of the Shrine Maiden Akari; though Morimichi himself was very reluctant in his role.
• Multiple Endings:
  • Hollow Reunion: The standard ending for defeating the Shrine Maiden of the Tied Rope. Chiyo saves Akari, and the two escape and have a Relationship Upgrade... except this "Akari" is actually Akari's Enemy Without who swapped places with her other half.
  • Yachiyo: Losing the battle with the true Shrine Maiden and not having the Spirit beforehand leads to Akari capturing Chiyo and making her a Sex Slave.
  • Abyss of Layers: If you defeat the Shrine Maiden with over 75 corruption and refuse Akari's request for you to leave the theater, then Chiyo absorbs Akari into herself, but the corruption drives her insane and turns her into a rampaging monster who corrupts everyone around her into losing all inhibitions, forcing Yakumo to stop her.
  • Missing Half: If you defeat the Shrine Maiden with over 75 corruption and leave the theater, then Akari fuses with her other half and passes on, breaking Chiyo; by the time we see her next, she's gone insane and thinks Akari is still around, becoming willing to have sex with anyone who claims to be Akari.
  • Transience: If you defeat the Shrine Maiden with over 75 corruption and refuse Akari's request for you to leave the theater, then Chiyo kills Akari and herself with her sword so they can be together, while Yakumo is left to continue doing his detective work.
  • Eternal Presence: If you defeat the Shrine Maiden with under 75 corruption and leave the theater, then Akari fuses with her other half and passes on, but Chiyo is able to move on and live a somewhat happy life.
  • Kizuna and Bonds: If you get either Transience or Eternal Presence, find an item in the warehouse in the last Chapter, and lose to the true Shrine Maiden, then Akari will assault Chiyo as in the Yachiyo end, but the stone will calm Akari down and allow herself to reincarnate as Chiyo's daughter, with an older Chiyo and Yakumo seen raising her while the spirit of Akari watches over them.
• Porn with Plot: The 18+ version is a typical erotic horror game where getting caught by a monster leads to an h-scene, and there are tons of them, but underneath that is a gradually unfolding story of two women, their lifelong friendship that deepens into something more, and the surrounding story of the cursed village that they are more connected to than they realize.
• Reincarnation Romance: Chiyo and Akari were once Yuki and “Nao” from an old village, and fell in love as Nao was imprisoned within the mansion storehouse to prevent her from becoming the new Human Sacrifice, intending to have Yuki take her place. A subsequent escape attempt went wrong and both ultimately were killed by the village, but Yuki eating Akari’s heart caused them to reincarnate, Yuki as Chiyo and Akari as a spirit who hangs around Chiyo. The two eventually rediscover their feelings for each other as the plot progresses.
• Self-Censored Release: The Steam release cuts off most of the sexual content from the game.
• Stealth-Based Mission: From Chapter 2 onward, you will have to sneak and evade the sight of villagers who will walk around various areas in order to progress. Chapter 2 is primarily one long stealth section consisting of evading the villagers, using obstacles to block their sight, and stealth-killing them when you can, but a few smaller sections are in Chapter 3.
• Tomato Surprise: It is not until the Interlude that we learn Akari, the best friend of the heroine Chiyo who seems to be a fellow ordinary university student, is invisible to everyone but Chiyo and is thought to be an imaginary friend by everyone else; Yakumo explains that Akari is actually a spirit who died long ago.
• Town with a Dark Secret: The now-destroyed village that the story revolves around is seemingly an ordinary Japanese village, but we eventually learn that they regularly performed ritual rape and Human Sacrifice of shrine maidens to appease their (non-existent) Great Serpent god. They also have a strict rule against leaving the village and shun anyone who breaks that rule if they return.
• Tragic Villain: Lord Morimichi Tsukishiro is the head of the village and runs the Human Sacrifice of shrine maidens that he subjected his wife and sister-in-law to, but his introduction makes it clear he disbelieves in the village religion and doesn't want to carry out any such acts. He sends Kyojiro Sagara to find another girl to take his daughter's place as the sacrifice while also having him research as much as he can about the history of the religion, hoping to find the truth about it and disprove it, as if he tried to stop the ritual openly the villagers would turn on him out of fear for their god's wrath. Unfortunately, they fail to find the info in time and he's forced to sacrifice his actual daughter, and the replacement gets killed soon after; then he is murdered by a villager who thought he botched the ritual.
• True Final Boss: Beating the Shrine Maiden of the Tied Rope and choosing to kill her leads to the standard ending of the game, but if you choose to spare her instead, the captured Akari reveals she is the true Shrine Maiden who swapped places with the "real" Akari and faces you in a more difficult gauntlet that leads to all the other endings.
• Your Princess Is in Another Castle!: The finale of the game has Chiyo finally go to rescue Akari from her imprisonment by the Shrine Maiden of the Tied Rope, but if you defeat her and then spare her, it turns out she is the "real" Akari who the other Akari swapped places with in order to trick Chiyo into destroying her good half; you have to face her in a second boss fight to save Akari for real.