Clannad (クラナド, Kuranado?) is a Japanese visual novel created by the software company Key, who also produced the successful titles Kanon and Air. Key announced in 2001 a release date of 2002 for Clannad and, after several postponements, finally released a limited version for the PC on April 28, 2004, and the regular version less than four months later on August 8, 2004. The visual novel was later ported to the PlayStation 2, PlayStation Portable, and Xbox 360. The gameplay in Clannad follows a linear plot line, which offers pre-determined scenarios and courses of interaction, and focuses on the appeal of the five female main characters. Jun Maeda, the main scenario writer of Clannad, believed that the title meant "family" or "clan" in Irish.

While both of Key's first two previous works, Kanon and Air, had been released first as adult games and then censored for the younger market like most bishōjo games, Key's third work Clannad was released for all-ages and does not contain risqué situations or even any fan service. Following Clannad's release, Key later produced an adult sequel-of-sorts entitled Tomoyo After: It's a Wonderful Life released on November 25, 2005 which expands the scenario of Tomoyo Sakagami, one of the five heroines from Clannad.

Clannad has made several transitions to other media: four manga series, the first serialized in the Japanese magazine Comic Rush, the second serialized in Comi Digi +, the third serialized in Dengeki G's Magazine, and the fourth in Dragon Age Pure; an animated movie by the animation studio Toei Animation released on September 15, 2007; two anime series including an original video animation by Kyoto Animation, which also animated the previous Key titles Air and Kanon; and, lastly, two sets of drama CDs, totaling nine in all. ADV Films will localize and distribute the first Clannad anime series in North America starting in April 2009.

Source: Wikipedia