Rider Wars Start

is the seventeenth episode of Kamen Rider Build. It features the debut of Ryuga Banjo's transformation into Kamen Rider Cross-Z Charge.
==Synopsis==
At last, the war has begun! Instigated by virtue of Hokuto through their prime minister's actions, the Touto government officially instigates the Kamen Rider as their military weapon. "I do not intend to become a tool of war" Sento replies. There is a reluctance in Sento's words though, as he realizes that the outbreak of this war was also due to him creating the Rider System and the Smash. Just what decision will these two warriors make?
==Plot==
to be added
==Cast==
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===Guest Casts===
*TV Announcer: 
===Suit Actors===
*Kamen Rider Build: 
*Kamen Rider Cross-Z (Charge): 
*Blood Stalk: 
*Castle Hard Smash: 
*Stag Hard Smash: 
*Owl Hard Smash: 
==Forms and Collectibles Used==
===Fullbottles===
*Bottle used:
**Build
***Biotic: Rabbit
***Abiotic: Tank
***Other: RabbitTank Sparkling
**Cross-Z (Charge)
***Biotic: Dragon (once in Twin Breaker)
***Abiotic: N/A
***Other: Cross-Z Dragon (once in Twin Breaker)
**Grease
***Biotic: N/A
***Abiotic: Helicopter
**Blood Stalk
***Biotic: Cobra
***Abiotic: N/A
**Castle Hard Smash
***Castle
**Stag Hard Smash
***Kuwagata
**Owl Hard Smash
***Fukurou
*Form used:
**Build
***RabbitTank Form, RabbitTank Sparkling Form
===Sclashjellies===
*Jelly used:
**Cross-Z Charge
***Dragon
==Errors==
*When Kazumi destroyed a Smash with his powered punch, after the Smash turns into a green flame, no human body is seen on the ground, even though Smashes should have turned back into their original human form after they are defeated.
**It is possible that the human casualty was simply obscured from view since the camera never focused on the exact spot where the Smash landed on again after it was defeated.
*When Banjo transforms into Cross-Z Charge for the first time, the standby tune from the Sclash Driver is inaccurate, as it only loops the beginning part of said tune.
==Notes==
*As part of Super Hero Time, this episode aired alongside episode 44, .
*Viewership: 3.3%
*The formula of the title:F_2=2^{{2^2}}+1=17 ()
*Fullbottles Obtained: Phoenix, Robot, Wolf, Smapho, Kuma, Televi
*Closing Screen Fullbottles & Sclashjellies:
**Kamen Rider: Cross-Z (Charge)
**Fullbottles:
***Biotic: Dragon
***Abiotic: N/A
**Sclashjellies:
***Dragon
*Count at episode end
**Bottles in Build's possession:
***Biotic: Rabbit, Gorilla, Taka, Ninjya, Panda, Harinezumi, Lion, Kaizoku, Octopus, Phoenix, Wolf, Kuma
***Abiotic: Tank, Diamond, Gatling, Comic, Rocket, Syoubousya, Soujiki, Densya, Light, Robot, Smapho, Televi
***Other: RabbitTank Sparkling
**Bottles in Cross-Z (Charge)'s possession:
***Biotic: Dragon
***Abiotic: Lock
***Other: Cross-Z Dragon
**Bottles in Grease's possession: Helicopter
**Bottles in Night Rogue's possession: Bat
**Bottles in Blood Stalk's possession: Cobra
**Bottles in Castle Hard Smash's possession: Castle
**Bottles in Stag Hard Smash's possession: Kuwagata
**Bottles in Owl Hard Smash's possession: Fukurou
**Jellies in Cross-Z Charge's possession: Dragon
**Jellies in Grease's possession: Robot
*The episode's title mirrors Kamen Rider Decades episode, Rider War: Prologue, and the Rider War concept as a whole.
*This episode doesn't introduce a recap of the last episode as prior episodes have.
*Incidentally, the premiere of Kazumi's debut was accompanied by a promo for the Blu-ray Box release of Kamen Rider Kiva, in which actor Kouhei Takeda previously starred as Otoya Kurenai.
*This episode features the first appearances of the Kuma, Televi, Helicopter, Castle, Kuwagata, and Fukurou Fullbottles.
*This episode features the live appearances of the Wolf and Smapho Fullbottles after their brief video appearance in episode 9.
*This episode features the first televised debut of the Phoenix and Robot Fullbottles after their appearance in Kamen Rider Heisei Generations Final: Build & Ex-Aid with Legend Riders.
==DVD/Blu-ray releases==
*Kamen Rider Build Volume 5 features episodes 17-20: Rider Wars Start, The Golden Soldier, The Forbidden Item and The Devil's Trigger.
*Blu-ray Collection 2 comes with 12 episodes.
Build Vol. 5.jpg|Kamen Rider Build Volume 5, DVD
91R ZCOJk0L. SL1469 .jpg|Kamen Rider Build Collection 2, Blu-ray
==External links==
*TV Asahi's official episode guide for ライダーウォーズ開戦.
*Toei TV's official episode guide for ライダーウォーズ開戦
==References==
Category:Kamen Rider Build episodes
Category:New Form Episode
Category:New Year Episode