The Truth of the Best Match

is the forty-first episode of Kamen Rider Build.
==Synopsis==
Shinobu Katsuragi, Sento’s father and the lead researcher behind the Pandora Box and Ryuga Banjo… is alive?! In order to confirm if this was true, Ryuga was given an important piece of data. The data contains a recording made by Shinobu himself relaying information on the designs of the Build System. Furthermore, there is information within that contains the truth behind all the Best Matches! “Rabbit” and “Tank”… just why are they considered to be “Best Matches”? When Sento starts to uncover the truth behind them, Misora’s expression suddenly starts to change…
==Plot==
to be added
==Cast==
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*: 
*, : 
*: 
*: 
===Guest Casts===
*: 
*Misora Isurugi (Child): 
===Suit Actors===
*Kamen Rider Build: 
*Kamen Rider Evol: 
*Stag Lost Smash: 
==Forms and Collectibles Used==
===Fullbottles===
*Bottle used:
**Build
***Biotic: N/A 
***Abiotic: N/A 
***Other: Genius
**Stag Lost Smash
***Kuwagata
*Form used:
**Build
***Genius Form
===Evolbottles===
*Bottle used:
**Evol
***Biotic: Cobra
***Abiotic: Rider
***Other: Evol Trigger
*Form used:
**Evol
***Cobra Form (Phase 1), Black Hole Form (Phase 4: Perfection)
==Errors==
*Sento claims that Shimizu was the first man to ever be turned into a Smash. However, Sento fought the Fang Smash during his first stint as Build an entire year before the series had started. Also chronologically, Build saved Sawa Takigawa from the Needle Smash the night before Build even fought Shimizu.
**This claim is most likely a callback to a Rider's "debut" fight, as Shimizu was the first antagonist to fight Sento after viewers were shown Build's first on-screen transformation.
==Notes==
*As part of Super Hero Time, this episode aired alongside episode 20, .
*Viewership: 3.4%
*Formula of the title:\underset{q}{\arg\max}[\forall_n\leq q-2,q^2+q+n=\rho]=41()
*Closing Screen Lost Fullbottles:
**Lost Fullbottles:
***Biotic: Kuwagata
***Abiotic: N/A
*Count at episode end
**Bottles in Build's possession: RabbitTank Sparkling, FullFull RabbitTank, Genius
**Bottles in Cross-Z's possession:
***Biotic: Dragon Magma
***Abiotic: N/A
***Other: Cross-Z Dragon, Cross-Z Magma Knuckle
**Bottles in Rogue's possession: Crocodile Crack
**Bottles in Evol's possession:
***Biotic: Rabbit, Gorilla, Taka, Ninjya, Panda, Harinezumi, Lion, Dragon, Kaizoku, Octopus, Phoenix, Wolf, Unicorn, Rose, Turtle, Kabutomushi, Kuma, Dog, Santa Claus, Spider, Tora, Kujira, Shika, Kirin, Penguin, Obake, Same, Hachi, Sai
***Abiotic: Tank, Diamond, Gatling, Comic, Rocket, Syoubousya, Soujiki, Lock, Densya, Light, Robot, Smapho, Keshigomu, Helicopter, Watch, Camera, Televi, Mic, Cake, Reizoko, UFO, Jet, Pyramid, Senpuki, Sukebo, Magnet, Bike, Sensuikan, Dryer, Castle
**Bottles in MadRogue's possession:
***Biotic: Bat
***Abiotic: Engine
**Jellies in Grease's possession: Robot, Dragon
**Evolbottles in Evol's possession:
***Biotic: Cobra, Rabbit
***Abiotic: Rider
**Evolbottles in Cross-Z's possession:
***Biotic: Great Dragon
***Other: Great Cross-Z Dragon
**Lost Bottles in Evol's possession:
***Biotic: Bat, Cobra, Shimauma, Fukurou, Kuwagata
***Abiotic: Hasami
*During the recap narration at the beginning of the episode, Gentoku makes references to himself not knowing how to buy a train ticket as well as his dislike of green peppers. These would eventually be demonstrated on-screen in Kamen Rider Prime Rogue.
*Sento Kiryu is the only one in Team Build to be transformed.
*It features the debut of the Fukurou and Kuwagata Lost Fullbottles.
*This episode marks the return and death of Kyoichi Shimizu since his last appearance in Episode 1.
==External links==
*TV Asahi's official episode guide for ベストマッチの真実
*Toei TV's official episode guide for ベストマッチの真実
==References==