Kamen Rider Wiki
Kamen Rider Wiki
Icon-build.png This article is about a/an transformation device in Kamen Rider Build.

"(Biotic Fullbottle name)! (Abiotic Fullbottle name)! Best Match! Are you ready? (Jingle followed by name)! Yeah!"
―Best Match form transformation announcement[src]

"Ready, go! Vortex Finish! Yeah!"
―Best Match finisher announcement[src]

"(Biotic Fullbottle name)! (Abiotic Fullbottle name)! Are you ready? (Funky music)"
―Trial Form transformation announcement[src]

"Ready, go! Vortex Attack!"
―Trial Form finisher announcement[src]

"(Fullbottle name)! Are you ready? (Jingle followed by name)! Yeah!"
―Transformation announcement with a Fullbottle that occupies both slots[src]

"(Biotic Fullbottle name)! (Abiotic Fullbottle name)! Super Best Match!"
―Best Match announcement with Hazard Trigger[src]

"Don ten kan! Don ten kan!"
―Looping standby announcement with the Hazard Trigger[src]

"Gata gata gotton! Zuttan zutan!"
―Vortex Crank turning announcement with the Hazard Trigger[src]

"Yay! Yay!"
―Vortex Crank turning announcement with the Genius Fullbottle[src]

"Gabu! Gabu!"
―Vortex Crank turning announcement with the Prime Rogue Fullbottle[src]

"Bura! Ciao!"
―Vortex Crank turning announcement with the Muscle Galaxy Fullbottle[src]

"Build Up!"
―Announcement whenever a device that occupies both slots is inserted along with the Hazard Trigger[src]

The Transformation Belt Build Driver (変身ベルト ビルドドライバー Henshin Beruto Birudo Doraibā) is the transformation device used by both Kamen Rider Build and Kamen Rider Cross-Z, and later used by Kamen Rider Grease and Kamen Rider Rogue for later additional forms.


The Build Driver is the first and foremost system developed as part of Project Build, using Fullbottles as its primary collectible device.[1]

A Hazard Level of 3 is required to be able to transform using the Build Driver, otherwise the anti-theft security measures on the Driver will activate and electrify the user to unconsciousness.


The Build Driver is composed of the following parts:

  • Vortex Charger (ボルテックチャージャー Borutekku Chājā) - The circular energy generator unit. By turning the Vortex Lever, the Vortex Charger spins, activating the internal Nitro Dynamo (ニトロダイナモ Nitoro Dainamo) engine, generating enough energy to transform and deal deathblows.
  • Vortex Lever (ボルテックレバー Borutekku Rebā) - The crank used to activate and operate the Build Driver. The faster the crank is spun, the more energy is developed.
  • Twin Fullbottle Slots (ツインフルボトルスロット Tsuin Furubotoru Surotto) - The slots that Fullbottles are inserted into. It takes in the Transgel Solid ingredients inside of the Fullbottles and feeds it to the Building Modules.
  • Building Modules (ビルディングモジュール Birudingu Mojūru) - An expansion device built into the Twin Fullbottle Slots. During transformation, it develops the Snap Ride Builder[2] (スナップライドビルダー Sunappu Raido Birudā) (or any other type of 'Builders'), a compression device resembling plastic model runners, allowing transformation to occur.
  • Safety Guard Case (セーフティガードケース Sēfuti Gādo Kēsu) - The outer parts. It utilises high-strength material with heat and impact resistance, allowing it to protect internal mechanisms. It is so strong that it can withstand Smash attacks.
  • Adjust Bind (アジャストバインド Ajasuto Baindo) - The yellow strap used to fix the Build Driver upon the waist. When the Driver is not in use, it is stored inside the Driver.
  • Qualifizer (クオリファイザー Kuorifaizā) - A biometric scanning device located in the black section at the rear of the Adjust Bind. It reads Hazard Levels, and will prevent transformation to anyone lower that a Hazard Level 3.
  • L&P Amplifier (L&Pアンプリファー L&P Anpurifā) - A converter installed inside the Driver that converts emotions into energy. The stronger the emotions, the stronger the Rider's attacks will be. This is due to their Hazard Level increasing/decreasing depending on emotions.



Kamen Rider Build transforms by inserting two Fullbottles into the Build Driver's Building Modules (ビルディングモジュール Birudingu Mojūru) and plugging them into the Twin Fullbottle Slots (ツインフルボトルスロット Tsuin Furubotoru Surotto). The user then turns the Vortex Lever (ボルテックレバー Borutekku Rebā), a crank that generates power to the Vortex Charge (ボルテックチャージャー Borutekku Chāji) energy core generator unit by turning the lever. This gives the Nitro Dynamo (ニトロダイナモ Nitoro Dainamo) inside the Vortex Charge the momentum it needs to generate power for transformation and finishers. Larger amounts of energy can be generated by increasing the momentum of turning the Vortex Lever and rotation speed of the Vortex Charge.

In a rare instance for Rider Belts, in Episode 1, the inner workings of the Build Driver were seen during transformation. As the Vortex Lever and Vortex Charge turns, it moves the gears and pistons inside the belt which pump essence from the Fullbottles out of their containers through pneumatic tubes, which move out of the belt and form the base for assembly of the suit. If the user is transforming into a Best Match form, the Driver then initializes the Snap Ride Builder[3] (スナップライドビルダー Sunappu Raido Birudā) after the essences have hardened into the Halfbodies. Afterwards, the Driver will yell out "Are you ready?" (「あーゆーれでぃ」 A Yu Redei?). To confirm and initiate transformation, one must give the voice command of "Transform!" (「変身」 Henshin), "Build Up!" (「ビルドアップ」 Birudo Appu) or "I'm ready" (「できてるよ」 deki teru yo) (humorously, the Build Driver will also respond to replies of "No I'm not!" (「ダメです」 dame desu)).[4] Once the confirmation voice command has been given, the Snap Ride Builder will collapse onto the user, snapping the two parts together and completing the transformation. The Snap Ride Builder will not appear if the user is moving during the transformation, while in some instances, the pneumatic tubes of the Snap Rider Builder will simply appear in a quick flash so as to speed up the transformation.[5]

The Build Driver is layered in an alloy called the Safety Guard Case (セーフティガードケース Sēfuti Gādo Kēsu), designed to resist high temperatures, high impacts of force and attacks by the Smash. As a security feature, the belt uses the Qualifizer (クオリファイザー Kuorifaizā) fastener to do a biometric scan of its wearer to determine if the intended user has a minimum Hazard Level of 3. If it is not, the belt will not function and go into a protective shutdown state, punishing the would be wearer. If the user does, the belt will continue to operate normally.

An ideal combination of two matching Fullbottles will create a Best Match (ベストマッチ Besuto Matchi) form, but any other imperfect combination is known as a Trial Form (トライアルフォーム Toraiaru Fōmu). The Build Driver did not originally announce Best Matches, but was later modified to do so by Sento Kiryu.

Kamen Rider Cross-Z transforms by inserting the Dragon Fullbottle into the Cross-Z Dragon, before inserting it into the Build Driver, and turning the crank.

When transforming into Cross-Z Magma by inserting the Dragon Magma Fullbottle into the Cross-Z Magma Knuckle before inserting it into the Build Driver and turning the crank, the Magma Ride Builder (マグマライドビルダー Maguma Raido Birudā) is summoned and pours Variable Magma over the Rider. This substance forms a casting of the Cross-Z Magma armor as numerous smoldering dragons rise up from the pool of lava. Once cooled and hardened, the Magma Ride Builder shatters the cast, releasing Cross-Z Magma.

The transformation into Grease Blizzard is mostly the same, with the North Blizzard Fullbottle being inserted into the Grease Blizzard Knuckle, the weapon inserted into the Driver, and, after turning the crank, summoning the Ice Ride Builder (アイスライドビルダー Aisu Raido Birudā) to submerge the Rider in liquid Variable Ice. The substance hardens into a mound of ice, before the Ice Ride Builder shatters the construct to reveal Grease Blizzard.


Main article: Vortex Finish

While transformed, Build/Cross-Z/Grease initiates a finishing move by turning the Vortex Lever. Build's Best Matches use the Vortex Finish (ボルテックフィニッシュ Borutekku Finisshu), and Build's Trial Forms use the Vortex Attack (ボルテックアタック Borutekku Atakku). Cross-Z' finisher is the Dragonic Finish (ドラゴニックフィニッシュ Doragonikku Finisshu), later followed by Cross-Z Magma's Volcanic Attack (ボルケニックアタック Borukenikku Atakku) and Volcanic Finish (ボルケニックフィニッシュ Borukenikku Finisshu). Grease's brief use of the Grease Blizzard Knuckle as Grease Blizzard had used finishers known as Glacial Attack (グレイシャルアタック Gureisharu Atakku) and Glacial Finish (グレイシャルフィニッシュ Gureisharu Finisshu).

Users (chronological order)

User Kamen Rider Episode Obtained Description
Takumi Katsuragi
Kamen Rider Build
Pre-series Takumi Katsuragi created the Build Driver as part of the Rider System in Touto, Hokuto, and Seito, later became a former member of Touto Institute of Advanced Matter Physics, then later created Faust, and its founder.

His Build Driver was secretly replaced with a experimental version by Blood Stalk shortly before his supposed death, and the original one would later be used by his new identity.

Evolto/Soichi Isurugi
The Severing Best Match (flashback) Blood Stalk had already been in possession of an incomplete and experimental version of Build Driver for an unknown period of time by the time of Takumi Katsuragi's supposed death.

As part of his plans, Stalk took Takumi's Build Driver and replaced it with the experimental one, causing him to be unable transform into Build and reverting the Gorilla Fullbottle into its empty form, leading to his murder. This soon later modified by Shinobu Katsuragi after Takumi's memory wiping events, but without the "Best Match!" announcement.

Sento Kiryu
Kamen Rider Build
Who Takes Off The Veil? (flashback) Sento was given Takumi's Build Driver by Evolto (under the identity of Soichi Isurugi) after being taken in by him.

Ryuga used this Driver for his first transformation and kept it for a short amount of time before Sento built a second one and gave it to him.

Misora briefly took it from him in an attempt to transform against Evolto, but it was taken from her by Gentoku to become Prime Rogue. Gentoku returned the Build Driver to Sento afterwards.

Ryuga Banjo
Kamen Rider Cross-Z
Burning Dragon (1st, borrowed from Sento)

Theory of Conspiracy (2nd)

In Episode 6, Ryuga attempted to transform using Sento's Driver, but his then-low Hazard Level prevented him from doing so.

When Night Rogue stole Sento's Driver, Ryuga retrieved it and used it to successfully transform into Cross-Z. Ryuga kept Sento's Driver until Sento built another one for him in next episode. The driver was taken by Kengo Ino but was then taken back by Sento and Ryuga.

Shinobu Katsuragi
Kamen Rider Build (Prototype)
Legacy of Doubt At some point, Shinobu seemed to modify the experimental version of the Build Driver that Blood Stalk created to trick Takumi before his memory washed away, which he used to become another Kamen Rider Build. As this prototype Driver is based on the original schematics, it does not announce Best Matches. After his death, his Driver went into the possession of Sento, who hid it inside the Purifier. Kazumi would later take it for his own usage despite Sento's warnings.
Kengo Ino
Kamen Rider Blood
Kamen Rider Build: Be The One After taking the Build Driver and Great Cross-Z Dragon from Ryuga and stealing the Hazard Trigger from Sento, he used it to transform into Kamen Rider Blood.[6] The driver is then taken back by Sento and Ryuga.
Kazumi Sawatari
Kamen Rider Grease Blizzard
An Oath to Be The One

After being given the Grease Blizzard Knuckle by Sento, Kazumi steals Shinobu Katsuragi's experimental Build Driver from Sento's lab in order to use it to transform into Grease Blizzard.

Gentoku Himuro
Kamen Rider Prime Rogue
Kamen Rider Prime Rogue

Gentoku snatched Sento's Build Driver out of Misora's hands in order to transform into Prime Rogue to fight against Evolto. Gentoku returned the Build Driver to Sento afterwards.

In the New World, Gentoku is shown with his own Build Driver that Sento created for him, which he uses to transform into Prime Rogue again to fight Down Fall.

Kamen Rider Build/Kamen Rider Killbus
Build NEW WORLD: Kamen Rider Cross-Z

After stealing the Build Driver from Sento, Killbus used it to transform into Kamen Rider Build.

Killbus subsequently stole a toy Sento had invented for Ryuga to sell and modified it into the Killbuspider, allowing him to transform into Kamen Rider Killbus. When Killbus was defeated, the Build Driver was destroyed.

Keiji Uraga
Kamen Rider Metal Build/Kamen Rider Phantom Build
Build NEW WORLD: Kamen Rider Grease

This additional Driver was created by Shinobu Katsuragi in the New World and was being shown to Simon Marcus by Gentoku Himuro when Down Fall ambushed them and stole the Driver. Keiji Uraga uses this version of the Build Driver along with the stolen Hazard Triggger (which is once again from Sento) to transform into Kamen Rider Metal Build.

Upon the defeat of Phantom Build, this Build Driver disintegrated along with Keiji.

Kamen Riders

Snap Ride Builders

Behind The Scenes


The voice of the Build Driver was provided by KORBY.[7]


  • The Build Driver is reminiscent of the Double Driver, using two differently themed devices to create a combination form.
    • It also shares some similarities with the Accel Driver, such as using the grip on the right side of the Driver to transform.
    • The design is also somewhat similar to the Gamer Driver and the Meteor Driver as both slots for the trinkets are on the left side of the driver instead of being on opposite sides while the right side has the rest of the controls.
    • The method of reading the Fullbottles in the toy version of the Driver is identical to the method of reading Shift Cars in the Shift Brace from Kamen Rider Drive, as both use a sliding pin-combination system.
  • The announcements are similar to those of Kamen Rider OOO and Ultraman GeedIcon-crosswiki.png as they both have the parts of the form announced before the actual form, and each/some of the forms have their own unique phrase included in the transformation.
  • In the Build Driver toy, the slots used for the Fullbottles in Best Matches don't matter, meaning that using Bottles in Rabbit-Tank and Tank-Rabbit placements will both give RabbitTank's announcement. Using Bottles in the opposite biotic/abiotic slot hasn't been explored in the show, however.
  • The idea that the Build Driver was to eventually be a mass-produced weapon for the series antagonist can be seen as an homage to the first series to have used the term "Driver" for their transformation devices, Kamen Rider 555, as they implemented a mass-produced variant of a Rider.
  • Unlike the name of Wizardriver or Decadriver, Build Driver is not called "Buildriver" because it was named for the Buildriver weaponIcon-crosswiki.png of Tokusou ExceedraftIcon-crosswiki.png in 1992.

Sento showing Build Driver's SD Card to Utsumi

  • In Kamen Rider Build: Raising the Hazard Level ~7 Best Matches~, the Build Driver somehow has an SD Card slot on the right side of the driver.
    • This is because the SD Card for the Build Driver contains a combat data from Build's battles and the fighting style of his foes. Although, the SD Card slot is not a feature for the DX toyline.
  • The Snap Ride Builders for RabbitTank Sparkling and RabbitTank Hazard, while being unique, also represent their particular origins:
    • RabbitTank Sparkling's Fullbottle creation using energy directly from the Pandora Box, and the symbol being present as part of the Snap Ride Builder.
    • The Hazard Trigger being designed after a gauge for pressurized liquid containers, and the Snap (Hazard) Ride Builder appearing as an injection molding template.
  • The Magma Ride Builder represents smelting, following the theme of chemistry involved in the Rider transformations, as Ryuga's stabilization of the Dragon Magma Fullbottle and the resulting transformation are similar to burning out impurities to obtain the required element.
    • The Ice Ride Builder is likely based on a chemical vat for frigid materials, due to its similar design to the Magma Ride Builder.
  • During the riders transformations, the Snap Ride Builders are usually gone during close up shots.
  • In the Korean Dub of Kamen Rider Ex-Aid, this belt was left undubbed and translated while the Korean Dub of Kamen Rider Build has the belt dubbed (excluding the Seito bottles).


See Also


Icon-build.png Kamen Rider Build
Kamen Riders
Sento Kiryu (Takumi Katsuragi) - Ryuga Banjo - Kazumi Sawatari - Gentoku Himuro - Evolto - Nariaki Utsumi - Shinobu Katsuragi
Movie-exclusive: Kengo Ino - Killbus - Keiji Uraga
Drivers/Transformation Gear
Build Driver - Transteam Gun - Nebulasteam Gun - Sclash Driver - Evol-Driver
Transformation Devices
Fullbottles - (Great) Cross-Z Dragon - Sclashjellies - Hazard Trigger - Cross-Z Magma Knuckle - Evol-Trigger - Grease Blizzard Knuckle - Killbuspider - Grease Perfect Kingdom
Drill Crusher - Hawk Gatlinger - 4Koma Ninpoutou - Kaizoku Hassyar - Fullbottle Buster - Steam Blade - Beat Closer - Twin Breaker - Muscle Glove - Solstall Wings - Giant Scratcher - Space Ride Arm - Spine Knuckle - Long Range Cleaner - Trash Converter - Gold Lio Gauntlet - Multi Deluge Gun
Pandora Box - Halfbodies - Fullbottle Holder - Build Phone
Vortex Finish - Hazard Level - Project Build - Sky Wall - Nebula Gas
nascita: Misora Isurugi - Soichi Isurugi - Sawa Takigawa - Kazumi Sawatari - Gentoku Himuro
Kamen Riders: Eiji Hino - Gentaro Kisaragi - Kouta Kazuraba - Takeru Tenkuji - Emu Hojo - Hiiro Kagami - Taiga Hanaya - Kiriya Kujo - Kuroto Dan - Parado - Sougo Tokiwa - Geiz Myokoin - Tsukuyomi
Prime Ministers: Taizan Himuro (Touto) - Yoshiko Tajimi (Hokuto) - Masakuni Mido (Seito)
Namba Heavy Industries Ltd.: Juzaburo Namba - Nariaki Utsumi - Haruhiko Wanibuchi - Guardian
Hell Bro's: Fu Washio - Rai Washio - Yoshikazu Takahashi - Norio Matsui
Aliens: Vernage
Gentoku Himuro - Evolto - Nariaki Utsumi - Takumi Katsuragi - Shingo Kuwata - Eita Kawai - Yoshikazu Takahashi - Norio Matsui
Normal Smash: Fang Smash - Needle Smash - Strong Smash - Burn Smash - Flying Smash - Mirage Smash - Square Smash - Press Smash - Ice Smash - Stretch Smash
Empowered Smash: Strong Smash Hazard - Press Smash Hazard - Stretch Smash Hazard - Flying Smash Hazard
Hard/Hazard Smash: Castle Hard/Hazard Smash - Stag Hard/Hazard Smash - Owl Hard/Hazard Smash
Clone Smash: Press Clone Smash - Stretch Clone Smash - Strong Clone Smash - Flying Clone Smash
Lost Smash: Owl Lost Smash - Stag Lost Smash - Castle Lost Smash - CD Lost Smash - Scissors Lost Smash - Zebra Lost Smash
Foundation X
Kaisers: Kaisei Mogami (World of Build, World of Ex-Aid) - Nebula Bugster
Blood Tribe
Kengo Ino - Ryoka Saiga - Mitsuomi Gobara - Evolto - Killbus - Akaba (imitation) - Aoba (imitation) - Kiba (imitation) - Remocon Bro's (imitation) - Engine Bro's (imitation)
Down Fall
Keiji Uraga - Simon Marcus (Phantom Crusher)