|This article is about a/an common trend in the Kamen Rider Series.|
"Henshin!" (変身 Henshin) is the Japanese word for "transformation/transform" meaning "to change or transform the body" or "equip". In the Kamen Rider Series, it is a common transformation call for what a Rider shouts when they are about to transform. It is said to have been the suggestion of producer Toru Hirayama, based on the Japanese title of Franz Kafka's Metamorphosis, which features a man transformed into an inhuman, bug-like creature against his will, a recurring theme of the Kamen Rider Series.
With the exception of the wordless transformations of Riderman, the riders of Kamen Rider The First & Kamen Rider The Next, the Oni Riders in Kamen Rider Hibiki, and Shin in Shin Kamen Rider: Prologue, the "Amazon!" cry of the Amazon Riders, and the "Set up!" (セットアップ Setto Appu) call of Kamen Rider X, every Japanese Kamen Rider uses the phrase when assuming Rider Form.
Some Riders have similar catchphrases for when they assume different forms while still in rider form, such as Kamen Rider Kuuga's "Cho Henshin" (超変身 Chō Henshin, lit. "Super Transformation") and Kamen Rider Ex-Aid's "Dai Henshin" (大変身, lit. "Great Transformation") phrases.