The story focuses on Hazumu Osaragi, a normal, albeit effeminate high school boy who is killed when an alien spaceship crash lands on him, only to be restored to health as a girl.

A single light novel written by Mako Komao and illustrated by the manga's artist was published by MediaWorks under their Dengeki Bunko imprint in January 2006.

Seven Seas Entertainment licensed the manga series for English-language publication in North America and released the five volumes between December 2006 and March 2008.

Media Blasters licensed the anime series, including the OVA, and released three DVD volumes between June and October 2007 with English-subtitles.

At the start of Kashimashi, a young high school boy named Hazumu Osaragi declares his love to classmate and close friend Yasuna Kamiizumi, but she quickly rejects him.

To rectify this, the alien in the ship named Hitoshi Sora brings Hazumu back to life, but inadvertently regenerates him as a female right down to the DNA level.

Tomari's good friend Ayuki Mari, an intelligent girl interested in the sciences, continuously observes the ongoing development of the love triangle while keeping a stance of watching from afar.

The very stoic Hitoshi originally came to Earth in order to study human emotions, especially those related to love, in an attempt to save his species from extinction.

The anime ends differently, with no life-threatening situation and Hazumu choosing Yasuna in order to help cure her worsening sight problem as it begins to degrade so she can no longer see girls as well.

[4] When thinking on how to write about true love, Akahori considered laughingly that in normal relationships between boys and girls, it eventually tends towards having sex.

Akahori knew this would be a problem, since normally changing a person's gender would cause complications, one of them being that the now-female character would invariably want to return to being male.

For this reason, Akahori devised that the character would not want to turn back into a male if there was the impact of the entire world already having accepted the fact that his gender had changed.

[9][10] Five bound volumes were released in Japan between January 27, 2005 and May 26, 2007 published under MediaWorks' Dengeki Comics imprint,[11][12] concluding the series at thirty-five chapters.

The manga was licensed for an English-language release in North America by Seven Seas Entertainment using the revised Hepburn romanization of the title, Kashimashi, unlike the traditional name of Kasimasi.

As implied in the title, the show was hosted by Kana Ueda, Yui Horie, and Yukari Tamura, who voiced Hazumu, Yasuna, and Tomari in the anime, respectively.

[20] A Kashimashi light novel, written by Mako Komao and illustrated by Yukimaru Katsura, was published by MediaWorks under their Dengeki Bunko imprint on January 10, 2006.

[21] The book, which is the same size as a manga bound volume, is printed in full-color for the first forty-eight pages which consists of a compilation of promotional art from the separate media types, character profiles with original sketches and comments on the characters, plus interviews from the voice actors of Hazumu, Yasuna, Tomari, Ayuki, and Jan Pu, and lastly original concept drawings of the school uniforms in the series.

[4] The anime series of Kashimashi was produced by Studio Hibari, directed by Nobuaki Nakanishi, and written by Jukki Hanada.

[25] There was a small additional portion during the bra shopping scene in episode two that was considered adult enough to be censored out of the television broadcast, but which was included in the DVD release.

Extras on the disc included two ten-minute talks between the voice actresses for the three main female characters, a small collection of Japanese television advertisements, and textless opening videos.

"Half") sung by Tamura, was used in episode twelve and was featured in the image song album Norte Amour released on April 5, 2006.

[46] An important aspect of the game (as in nearly every visual novel) are the "decision points" which appear every so often which give the player the chance to choose from a limited number of options.

The first volume was named as Newtype USA's Book of the Month for December 2006, and the review noted Seven Seas Entertainment's "fan-focused" translation, which retained the honorifics and much of the Japanese wordplay without efforts to localize the humor for the mainstream American market.

[48] The review goes on to state that "for fans of more mainstream romantic productions, it's a neat twist on the traditional love-triangle formula, and a charming alternative to boys meeting girls.

"[50] The second volume of the manga was positively reviewed at Anime News Network by Theron Martin, who wrote: "With its second volume the title pushes fully into the realm of romantic comedy, liberally sprinkling its story with humorous asides, pratfalls, and anecdotes while still dealing head-on with the much more serious and involved love triangle springing up around Hazumu.

"[1] In ANN's review of manga volume three, Theron Martin wrote, "The artistry of Yukimaru Katsura rarely devotes more effort to backgrounds than necessary, but its strength has always lain in the character designs and costuming.

[52] In a review of the first manga volume by Matthew Alexander at Mania.com, he thought that while "stories with love triangles or gender-switching protagonists have been done before...Hazumu's change into a girl explores romance between people of the same sex in an interesting and comedic way.

[57] Finally, for the third volume, Carl Kimlinger wrote that the writers made an ill-advised attempt to remove he "bitter" from "bittersweet" by tacking on plot developments which are unconvincing in the OVA, but that it ultimately has a "deeply satisfying conclusion".

Beveridge goes on to state "the mild moments of it are tacky and bad", but "when it comes to the core cast of characters, it's all solid material that is very enjoyable.

"[60] Finally, for the third volume, Beveridge wrote that "despite the issues with how the series turns in the bonus OVA episode, Kashimashi has proven to be quite a lot of fun for the situations it presented."