Kamen Rider Fourze (仮面ライダーフォーゼ,Kamen Raidā Fōze?) is a Japanese tokusatsu drama in Toei Company's Kamen Rider Series, being the thirteenth series in the Heisei period run and the twenty-second overall. It began airing on September 4, 2011, the week following the conclusion of Kamen Rider OOO, joining Kaizoku Sentai Gokaiger, later Tokumei Sentai Go-Busters, in the Super Hero Time lineup. Trademarks on the title were filed by Toei in April 2011. The series commemorates not only the Kamen Rider Series' 40th anniversary but also the 50th anniversary of spaceflight, which began with Yuri Gagarin's Vostok 1 flight in 1961. The show's catchphrase is "Switch on youth 'cause space is here!" (青春スイッチオンで宇宙キター！,Seishun suitchi on de uchū kitā!?), referencing the Fourze Driver (フォーゼドライバー,Fōze Doraibā?) transformation belt which gets its various powers from devices called Astroswitches (アストロスイッチ,Asutorosuitchi?) to conjure attachments to Fourze's limbs. As with the two previous series, the protagonist of Fourze made his debut in the annual summer film of the show's direct predecessor, appearing in Kamen Rider OOO Wonderful: The Shogun and the 21 Core Medals.
"Space, the limitless bounds of cosmic energy, and it's a wonderful world. This youth uses the Astro Switch to open the gates to the future. Space on your hands! Seize the youth and open your hands to grab the space!"
Amanogawa High School has become the center of strange happenings, and things only get stranger when the bad boy styled transfer student Gentaro Kisaragi attempts to make friends in his own unique way, reuniting with childhood friend and self-professed space travel otaku Yuki Jojima, all while gaining the ire of loner Kengo Utahoshi and the school's queen bee Miu Kazashiro and her enforcer jock boyfriend Shun Daimonji , as garishly styled social butterfly JK and goth girl Tomoko Nozama watch on.
When monsters called Zodiarts begin to appear on campus, Kengo and Yuki attempt to use the strange devices they have found in the Rabbit Hatch lunar base a year ago that they can access through a locker on an off-limits part of campus to fight them. However, Gentaro interferes in their plans, in part due to Kengo's body unable to handle the strains of battle, and uses the devices to transform into Kamen Rider Fourze. As times goes on, the group gained a new member for the Kamen Rider Club, Ryusei Sakuta who is an exchange student from Subaruboshi High, concealing his identity as Kamen Rider Meteor. Eventually everyone found out when Ryusei killed Gentaro. Tachibana toke Ryusei's transformation and everyone was shocked when Meteor's identity was revealed.
Earning Kengo's trust and forgiveness, Ryusei is re-allowed the Meteor gear and fights alongside Kamen Rider Fourze and the rest of the KRC against the Zodiarts. However, to keep the Anti-Zodiarts Organization a secret, Ryusei must not transform in front of a Zodiart, until Tachibana reveals his identity as Virgo Zodiarts.
Four short crossover episodes, collectively titled Kamen Rider Fourze × Crayon Shin-chan (仮面ライダーフォーゼ×クレオンしんちゃん,Kamen Raidā Fōze × Kureon Shin-chan?), between Kamen Rider Fourze and Crayon Shin-chan were shown in each show's time slots during April 2012 to promote their respective series' new films: Kamen Rider × Super Sentai: Super Hero Taisen and Crayon Shin-chan: The Storm Called!: Me and the Space Princess. The characters will crossover in two episodes of each respective series. The story follows Shin-chan teaming up with Kamen Rider Fourze in order to go to space and rescue Shin's younger sister who had been taken to Planet Himawari to become its princess. The first and fourth episodes feature both anime and live-action while the second and third were entirely animated.
This season was originally going to have been about the Kamen Rider Club investigating various urban legends about Kamen Riders, and would have featured appearences of many past Kamen Rider actors, however, this was scrapped due to it being too similiar to Kamen Rider Decade.
This series contains the most used of Ending Themes in Neo-Heisei period, being used it almost every episodes, except for some occasions. The other just use Ending Themes for rare occasions.
This is the first series since Kamen Rider Agito to not feature an original evil Rider/Anti-hero Rider in its films or respective show.
This is the only post-Kamen Rider Kuuga Heisei series to not include a Tertiary Rider.