The danka system (檀家制度, danka seido^?), also known as jidan system (寺檀制度, jidan seido^?) is a system of voluntary and long-term affiliation between Buddhist temples and households in use in Japan since the Heian period. In it, households (the danka) financially support a Buddhist temple which, in exchange, provides for their spiritual needs. Although its existence long predates the Edo period (1603–1868), the system is best known for its repressive use made at that time by the Tokugawa, who made the affiliation with a Buddhist temple compulsory to all citizens.

During the Tokugawa shogunate, the system was turned into a citizen registration network; supposedly intended to stop the diffusion of Christianity and help detect hidden Christians, it soon became a government-mandated and Buddhist temple-run system to monitor and control the population as a whole. For this reason, it survived intact long after Christianity in Japan had become a spent force. The system as it existed in Tokugawa times is sometimes called terauke system (寺請制度, terauke seido^?) because of the certification (or terauke, because the tera, or temple would issue an uke, or certificate) issued by a Buddhist temple that a citizen was not a Christian.

System of a Down, also known by the acronym SOAD and often shortened to System, is a rock band from Southern California, formed in 1994. It consists of Serj Tankian (lead vocals, keyboards, rhythm guitar), Daron Malakian (guitar, vocals), Shavo Odadjian (bass, background vocals) and John Dolmayan (drums).

The band achieved commercial success with the release of five studio albums; from which three debuted at number one on the Billboard 200. System of a Down has been nominated for four Grammy Awards, and won the award in 2006 for Best Hard Rock Performance for the song "B.Y.O.B.". The group went on hiatus in August 2006, but reunited in November 2010, embarking on a worldwide tour in 2011.

Serj Tankian, Daron Malakian, and Shavo Odadjian all attended Rose and Alex Pilibos Armenian School while children, although because of their eight-year age difference they did not meet until 1992 while working on separate projects at the same recording studio. They formed a band named Soil with Tankian on vocals and keyboards, Malakian on vocals and guitar, Dave Hakopyan (who later played in The Apex Theory/Mt. Helium) on bass and Domingo "Dingo" Laranio on drums. The band hired Shavo Odadjian (another Rose and Alex Pilibos alumnus) as manager, although he eventually joined Soil as rhythm guitarist. After three years, only one live show, and one jam session recording, Hakopyan and Laranio quit the band, feeling that it was not going anywhere.

Jah Jah, also known as MC Jah Jah, is the professional name of Janine Gordon, a white, female rapper, photographer and multimedia artist from Brooklyn, New York.

Jah Jah got her start in rap by becoming acquainted with many people involved in the Brooklyn, underground hip hop scene during the '90s. It was here that she met many other artists such as Redman, Chubb Rock, and The Beatnuts."I was so encouraged meeting Redman and The Beatnuts, Redman called me out in his song back in 97, 'Jah Jah I go Ca Ca,' so I have these people, people encouraging me," stated the rapper in an interview. She has a very wide fan base on Myspace and has experienced some success with her music overseas in Brazil. Jah Jah was able to remain within the top 10 artists for over a year on the Myspace music chart.

In 2005, Jah Jah filed a copyright infringement lawsuit against 50 Cent and Dr. Dre for allegedly stealing her music and using it illegally for 50's Massacre album.

Jah Jah has art, notably photography that has appeared in magazines such as Arena and galleries in New York, San Francisco,Europe and Brazil. Her visual art work is credited under her real name, Janine Gordon. She also has a Master's Degree in Fine Art from New York University.