This article is about a/an transformation device in Kamen Rider Hibiki.

The Henshin Onsa (変身音叉 lit. "Transformation Tuning Fork") is a transformation device resembling a tuning fork. It is the most commonly used transformation device among the Oni Kamen Riders of the organization Takeshi, usually those whose arsenal revolves around the percussion. It is said to be the simplest of all transformation devices to make, yet has the capability to unlock the greatest power within all Oni that use it. It has two forms: 'cellphone mode' and 'tuning fork mode'. While in the form of a cellphone mode, its Oni's face can not be shown, and the two prongs should be flipping out to reveal it. Furthermore, the Oni symbol is at the end of the holder, and the device is placed on the right side of the belt.


There are several functions on Henshin Onsa:

  • An Oni's transformation device, especially for percussion-type Oni. There is also another type of Oni that uses this device to transform.
  • It can convert Disk Animals to 'animal mode'. Onsa needs to be knocked on Disk Animal which is still in the 'disc mode'. The soundwave turns the Animal Disk into colored, straight into the 'animal mode' after being released.
  • Onsa can also playback the sound or video data collected by the Disk Animals.
  • The design is like a mobile phone, where Oni needs to open it just like that electronic device when using it, it also has a kind of ringtones that will ring when Disk Animals returns from its investigation.
  • It also has a function to call Disk Animals without waiting for their return. Oni needs to 'open it', tapping it, lifting it to the forehead, then pointing to the direction where the Disk Animal is released (example: sky for Akane Taka, water surface for Kihada Gani, etc.). Next, Oni made an interesting signal twice.

How to Use

Transformation to Oni form

To change to Oni form, Oni who uses this device needs to 'opening' Onsa like a cell phone, convert it to a 'tuning fork mode'. Then, this device blade will be tapped (or vented) on any hard surface, and will produce a special sound wave, then lifted precisely toward the user's forehead, forming a small Oni face. Upon completion of the transformation, Henshin Onsa will be restored to the right of the belt.

List of Henshin Onsa

Unlike the modern Oni, all Oni in different type can transform with a Henshin Onsa, and most of those devices are unnamed. It can possessed a 'katana mode' called the Meitō - Onsaken (鳴刀·音叉剣 lit. "Echo Sword: Tuning Fork Sword").

  • Users:
    • Kamen Rider Kabuki: Black Henshin Onsa (黒の変身音叉 Kuro no Henshin Onsa).
    • Kamen Rider Nishiki: Red Henshin Onsa (赤の変身音叉 Aka no Henshin Onsa), with a rough blade.
    • Kamen Rider Habataki: Golden Henshin Onsa (金色の変身音叉 Konjiki no Henshin Onsa), with the addition of brown color on the eyebrows on its Oni's face.

Henshin Onsa - Onkaku (変身音叉·音角 lit. "Transformation Tuning Fork: Sound Angle") is the most current version of Onsa. Used by most Taiko Oni today. Its Oni's face part is golden, as well as the tip of its handle, which is black, and an ordinary blades. Because the shape is specially designed to resemble a mobile phone, as well as the addition of other new functions such as reading Disk Animals recording data, the function of transforming it into the Onsaken is no longer possible. The colors on the Onkaku can be changed, depending on the wearer.

There are several different Henshin Onsa in Midori Takizawa's laboratories. It does not revealed who uses it, nor whether the device is a prototype version or not. The Onsa used by Midori (when turning on Shikigami paper) is very different from existing Onsa, it may have no function to transform the user into Oni form.



  • Henshin Onsa is the first transformation device for Heisei Rider series that is not in the belt form, where it is used by it’s main Rider, Hitoshi Hidaka/Kamen Rider Hibiki to turn into Oni.
Icon-hibiki Kamen Rider Hibiki
鬼 Oni
Primary: Hitoshi Hidaka - Iori Izumi - Tomizo Todayama - Zaomaru Zaitsuhara
Other: Daisuke Danda - Sakae Saeki - Eiki - Shuki - Akira Amami - Kyosuke Kiriya - Shouki
Ancient Sengoku Era Oni: Hibiki (past) - Ibuki (past) -Todoroki (past) - Kabuki - Tohki - Kirameki - Nishiki - Habataki
猛士 Takeshi
Ichiro Tachibana- Asumu Adachi - Kasumi Tachibana - Hinaka Tachibana - Midori Takizawa - Kounosuke Kogure
Allies: Hitomi Mochida - Ikuko Adachi
魔化魍 Makamou
Leaders: The Real Man and Woman - The Man and Woman - Black Puppet - White Puppet - Super Douji and Hime
Giant Type Makamou: Tsuchigumo - Yamabiko - Bakegani - Ittanmomen - Ooari - Okubi - Otoroshi - Ubume - Yamaarashi - Oonamazu - Amikiri - Kamaitachi - Notsugo
Summer Type Makamou: Dorotabou - Kappa - Bakeneko - Uwan - Tengu - Hitotsumi
Special Makamou: Nanashi - Kasha - Yobuko - Kodama - Satori - Rokurokubi - Orochi
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