This article is about a/an episode in Kamen Rider Build.

That One with the Best Match (ベストマッチな奴ら Besuto Macchi na Yatsu ra) is the first episode of Kamen Rider Build. It features Build's on-screen transformation (in the show) as RabbitTank. It also features the debut of Build's HarinezumiTank form.


A mysterious object known as the Pandora Box was brought back from Mars. In effect, Japan was divided into three by giant walls produced from the box. 10 years have passed since that day. This story takes place in one of the city capitals, Touto. Mysterious organisms known as Smash are terrorizing humanity. A physicist saves people from the Smash and pursues the mystery hidden within the Pandora Box. His name is Sento Kiryu. People call him... the Kamen Rider.


Ten years ago, Japan became the first country to successfully send a manned probe to Mars. In what appeared to be the ruins of an extinct Martian civilization, an astronaut discovered a mysterious cube, which would come to be known as the Pandora Box. At the return ceremony for the expedition, a security guard suddenly rushed forward for the Pandora Box. As he touched the artifact, a flash of light erupted, and a massive wall rose from the ground, splitting Japan into three regions: Hokuto in the north, Seito in the west, and Touto in the east. The rising of the wall, now known as the Skywall Disaster, prompted regional tensions, dividing Japan even further.

In the present day, Touto's government is in possession of the Pandora Box, and has formed the Touto Institute of Advanced Matter Physics, headed by Gentoku Himuro, in order to decipher the artifact before foreign countries attempt to seize any of the three regions. There have been numerous reports of Touto citizens being attacked by strange creatures known only as "Smash", as well as a mysterious hero nicknamed "Kamen Rider" saving people from the Smash. While being interviewed by journalist Sawa Takigawa, Himuro is informed about Sento Kiryu, a researcher applicant with promising test results. Later that night, Takigawa is attacked by a Smash, but is saved by the Kamen Rider. The Rider extracts something from the Smash using an Empty Fullbottle upon defeating it, causing it to revert to a human form.

The next day, Sento awaken from his sleep as he reminded about some part of his past memories, including being experimented by scientists using gas masks, lead by a bat man. Upon his awake however, he saw his face being smeared by marker. Sento already know who did it, but temporarily diverted as the Fullbottle he extracted last night had been purified by Misora into Hedgehog (Harinezumi) Fullbottle. As Sento visibly excited, Misora was too tired to even respond to Sento, and go to his bed to sleep. In act of revenge, Sento then smear her face with marker (drawn many physics formulas) before leaving his underground base.

Upon reaching the surface of his underground base, namely cafe Nascita. Sento is greeted by the cafe owner, Soichi Isurugi which startles him in return. After showing Soichi Harinezumi Fullbottle, Soichi promptly asked Sento if he get any clue about his past life. Sento replied that aside of Scientists in Gas Mask, humans experimentation and the mysterious bat guy, he still lacking. Soichi then reminds him that he had a year worth of rent for the underground base. Sento, now realizing that the rent bills are the reason why Soichi ask him to apply for the job at Touto Institute of Advanced Matter Physics and that he's about to get late on his first day, showing Soichi another of his invention, Build Phone and Lion FullBottle. Soichi teases him if he were to call in sick, but Sento instead use both of them into Machine Builder. After Sento set off, the view changes to a sewer where a topless fugitive make his escape. Then, after changing clothes, Touto Guardians manage to track and found his location.

At Touto Institute, Gentoku gives Sento some orientation about what he is about to research, Mainly Pandora Box. Upon asking about Sento applicant resume, Gentoku was visibly surprised after he know that Sento is amnesiac. He later ask Sento if he know about Skywall Incident, which Sento complies. Gentoku added that the effect of Skywall isn't just with region separation, but everyone there turned Aggressive over the artifact.

Suddenly, Gentoku receive report that the fugitive, Banjo Ryuga had defeat the Guardians who surround him Bare handed, and now making his escape once more using a stolen Guardian bike. Sento also informed about this discreetly by Soichi along with the fact that Ryuga was once a pro fighter, which get banned for life for Fight Fixing. Ryuga also accused for murdering one of Touto institute researchers, Takumi Katsuragi. Sento later decide to chase him personally with Soichi guiding.

Sento successfully intercept Ryuga by exploding the path in front of him. Ryuga asked who is sento, which Sento replied that he'll about to catch him for his crimes. Ryuga however adamantly exclaim that he never killed anybody. Sento didn't belive him at first, until he mentioned about being used as Guinea pig. As Sento took interest for it, Ryuga strikes Sento and manage to get the upper hand. Sento then use the Rabbit FullBottle ability to strikes back successfully.

Taken aback, Ryuga then explain that the Gas Masks scientist also experiment upon him. He remember a bald security guard inject him with something that knocked him down. Then, the Gas Masks Scientist starts to dose Ryuga with Nebula Gas. Halfway though, Ryuga manage to escape, beat some of the scientists and run away. Sento then ask if Ryuga had known the Bat man which Ryuga angrily exclaim he had known nothing about him. However, their argument cut short as a Smash appeared and start attacking them. Ryuga manage to fight the Smash Barehanded, but the Smash is too strong for Ryuga to handle. Sento then admires his spirit and Transform into Build Rabbit Tank Form.

The battle between Build and the Smash continues as Sento use Harinezumi Tank Form to counter with the Smash strength, before reverts back to Rabbit Tank form to activate his Vortex Finish. After he extract the Smash essence in a empty FullBottle, Ryuga realize that the Smash is another person who goes the same experiment with him. However, upon further interrogation, the man experienced Short term memory loss. In despair, Ryuga beg Build to believe in him. Build then conclude that the experiments is to turn people into Smash. Unfortunately, Gentoku, Utsumi and some Touto military forces arrived as ask Build to hand Ryuga to them.

Ultimately, Build decide to trust Ryuga and helped him escape, thus making him a fugitive as well. After their successful escape, the bat man appeared and announce the beginning of war.


Guest Casts

Suit Actors


  • Bottle used:
    • Build
      • Biotic: Rabbit, Lion (in Build Phone), Harinezumi
      • Abiotic: Tank
    • Night Rogue
      • Bat
  • Form used:
    • Build
      • RabbitTank Form, HarinezumiTank Form


  • While Sento is explaining his the mechanics to his Build powers to Misora, there is one shot of him all cleaned up, similar to the state he was while he was leaving his lab. This could be due to a mis-arrangement of footage shot before and after the lab explanation scene.
  • When Sento cranks the lever to transform in front of Ryuga, he cranks the lever slowly, but in the next close-up shot of his driver, he's unexplainably cranking it twice as fast as before.


Build EP1 CS
  • Closing Screen Fullbottles:
    • Kamen Rider: Build
    • Fullbottles:
      • Biotic: Rabbit
      • Abiotic: Tank
  • Count at episode end
    • Bottles in Build's possession:
      • Biotic: Rabbit, Harinezumi, Lion, Kaizoku
      • Abiotic: Tank, Diamond, Gatling, Soujiki, Light
    • Bottles in Night Rogue's possession: Bat
  • Just like Ex-Aid's first episode, this episode takes its name from part of the main Rider's transformation announcement (i.e. Best Match).
  • The Sky Wall incident 10 years ago initially does not seem to fit with the rest of Kamen Rider continuity, since the incident was said to have divided Japan into three separate districts; however, Japan was shown to be intact throughout the past 10 seasons of the Kamen Rider Series.
  • References to the original Kamen Rider:
  • The color of the spacesuit on Mars was adjusted with a filter in this episode.

DVD/Blu-ray releases

External links