The Japanese era calendar scheme is a common calendar scheme used in Japan, which identifies a year by the combination of the Japanese era name (年号, nengō^?, lit. year name, Chinese: niánhào) and the year number within the era. For example, the year 2012 is Heisei 24. As elsewhere in East Asia, the use of nengō, also known as "gengō" (元号^?), was originally derived from Chinese Imperial practice, although the Japanese system is independent of the Chinese, Korean and Vietnamese era-naming systems. Unlike some of these other similar systems, Japanese era names are still in use. Government offices usually require era names and years for official papers.

The four era names used since the end of the Edo period in 1868 can be abbreviated by taking the first letter of their romanized names. For example, S55 means Shōwa 55 (i.e. AD 1980), and H22 stands for Heisei 22 (AD 2010). At 64 years, Shōwa is the longest era to date.

The system on which the Japanese era names are based originated in China in 140 BC, and was adopted by Japan in AD 645, during the reign of Emperor Kōtoku.

A regnal name, or reign name, is a formal name used by some monarchs and popes during their reigns. Since medieval times, monarchs have frequently chosen to use a name different from their own personal name when they inherit a throne.

The new name (or sometimes the old one, confirmed) is followed by an ordinal to give a unique name for the period when the monarch is on the throne. However, in the case of a personal union, the same ruler may carry different ordinals in each state, as they are each assigned chronologically; but some may have more (or less) precursors of the same Christian name (usually from a different dynasty).

In parts of Asia, monarchs take era names. Even where that is not the case, individual rulers (often long-lived ones) — instead of a whole dynasty, as is the case with Georgian, referring to several Georges of the Hanoverian dynasty — may become eponymous of their age or the zeitgeist of an epoch. Examples include (from the United Kingdom) Victorian (even applied to the rest of the world) or Edwardian.

Rafael Castillo (born September 17, 1982), better known by his stage name De La Ghetto, is an American reggaeton singer/rapper originally of the duo Arcángel & De La Ghetto.

Rafael was born in New York and raised in San Juan, Puerto Rico. He was born to a Dominican father and Puerto Rican mother, and he later found out that he is of Chinese descent from his maternal grandfather. In 2004, he collaborated with reggaeton artist Arcángel (born Austin Santos) to form the duo Arcángel & De la Ghetto; the group debuted with the single "Pégate", which was featured on Naldo's mixtape Sangre Nueva in 2005. He along with Arcángel signed to Zion's label Baby Records, and have appeared on numerous reggaeton albums including the compilation Mas Flow: Los Benjamins. In 2006, De la Ghetto began his solo career and appeared the next year on two hit singles, the remix of "Siente el Boom" by Tito el Bambino and a collaboration with Randy, "Sensación del Bloque". De la Ghetto's solo debut album which has been watched on Youtube over 26 million times. Masacre Musical was released in 2008.Masacre Musical peaked at #46 on the Billboard Top Latin Albums chart in the U.S.; its single "Tu te Imaginas" peaked at #33 on the Billboard Hot Latin Tracks chart.

Ramón Luis Ayala Rodríguez (born February 3, 1977), known artistically as Daddy Yankee, is a Latin Grammy Award-winning Puerto Rican reggaeton recording artist. Ayala was born in Río Piedras, the largest district of San Juan, where he became interested in music at a young age. In his youth he was interested in baseball, and aspired to become a Major League Baseball player. He was unable to continue this sport when he received an injury to one of his legs, leaving him unable to walk correctly. He then became involved in the underground rap movement that was in its early stages in Puerto Rico, later to be called reggaeton. After receiving lessons from several artists within the genre, he developed an independent career, first recording in a production titled Playero 37. After this he began to produce independent albums. His first solo album was No Mercy. He subsequently formed a duo with Nicky Jam, and then continued his solo career with the releases of El Cartel and El Cartel II. This led him be one of many pioneers of the reggaeton genre earning him the nickname "El Cangri".