Tenchi Muyo! (天地無用! Tenchi Muyo!), is an anime and manga series about a boy named Tenchi Masaki and the alien women that love him.

The original series, Tenchi Muyo! Ryo-Ohki, was a six episode OVA (Original Video Animation or Direct-to-Home Video) series; released in Japan in 1992–93. As its popularity grew, it spurred a seventh episode (also known as the Tenchi Special) and the standalone Mihoshi Special. In 1994-95, the second OVA series was created and released, featuring episodes 8–13. From 2003 to 2005, a third OVA series was released, with episodes 14–19, centering around the three goddesses introduced in the second OVA series. This is then followed by a special twentieth episode which centered around some of the remaining plot threads towards Tenchi's mother, as well as Noike, who was introduced in episode 15. The series can be somewhat confusing to newcomers because it has several continuities, although due to later creative changes many consider the original OVAs 'true' canon.

Before the popularity of series like Love Hina, to American fans Tenchi Muyo! set the benchmark for a series with a somewhat meek but kind male lead surrounded by attractive but often bizarre women, an anime subgenre (harem comedy) which would later become common. The TM franchise is also well-known in having a manga developed after an animated version was released, when typically the reverse is true.

Tenchi Muyo! was one of the early successes for AIC, the animation company behind it, which went on to create El-Hazard, Battle Athletes, Oh My Goddess!, Dual! Parallel Trouble Adventure and many other anime series. The main artist for the series is Masaki Kajishima.

The name of the manga is a play on words. Tenchi muyo (天地無用?) in Japanese means "This way up", a phrase written, for example, on boxes to show they should not be upturned. The word muyo also means "unnecessary", thus with a lead character "Tenchi" this name could also mean "unnecessary Tenchi" and is more often than not translated to "No need for Tenchi" (even so far as the episode titles for the "Universe" series to have the running gag of having the titles start with "No need for...")

The three major series continuities are Tenchi Muyo!, Tenchi Universe, and Tenchi in Tokyo. The first series, TM!, is the original OVA (Original Video Animation) which introduces the core characters. The other two are spin-offs that utilize the same characters, with the addition of Kiyone Makibi, though the backstory is quite different from the original OVAs. The first of the spin-offs was Tenchi Muyo! TV (also known as Tenchi Universe), in 1995; it is a twenty-six episode TV series that retells the original series differently. This anime was one of few anime to be broadcast on PBS member station KTEH San Jose, according to the ANN.

The Tenchi Muyo OVA series also known as Tenchi Muyo! Ryo-ohki is a 20 episode anime series that was first released in Japan in 1992 based off the manga. All three series were produced by AIC in Japan. While for the US versions, the first two series were licensed and distributed by Pioneer Animation (Now Geneon Entertainment) and the third series was licensed and distributed by FUNimation Entertainment.

The distribution of the first OVA series was originally started in September 1992 and released six episodes that lasted until 1993. The first series was so sucessful that a seventh special episode was released in January 1994, followed by a Second OVA series with six additional episodes that begun distribution in September 1994 and lasted for one year until September 1995. However the Second OVA series ended on a cliffhanger and it wasn't until nearly eight years later in 2003 that a third OVA series was distributed in Japan. The third OVA series ended the Tenchi Muyo OVA storyline with six episodes followed by a special episode released in September 2005 that concluded the storyline.

The three OVA series, as well as the spinoff, Tenchi Muyo! GXP, are considered to be the official canon series.

- From Wikipedia