Big5 or Big-5 is an character encoding method of unknown origin for the Chinese language. Its Mainlander equivalent is GB.
Big5's Chinese name is Da Wu Ma (大五碼), means "Big Five Encoding." But it is unknown whether which language is the origin of the translation in this case. And the significance of the name is unclear too. The only parallel found in Chinese is "the big five metals" (大大金), which are commonly used in metallurgy. Perhaps the name is to convey its potential importance and wide-spread usage.
According to some accounts, the Big5 encoding was
popularized by its adoption in several commercial software packages,
especially the ET chinese system which ran on MS-DOS.
Nevertheless, the Taiwanese government declared it their standard in mid-1980s. However, Big5 was already the de facto standard by that time.
The original Big5 character set is sorted first by usage frequency, second by stroke count, lastly by KangXi Radicals.
The original Big5 character set missed many commonly used characters. To solve this problem, each vendor developed its own extension. The ETen extension became part of the current Big5 standard through popularity.
Hong Kong also adapted Big5 for character encoding. However, Cantonese uses many rare Chinese characters that were not available in the normal Big5 character set. To solve this problem, Hong Kong Government created the Big5 extensions "Government Chinese Character Set" in 1995 and "Hong Kong Supplementary Character Set" in 1999. The Hong Kong extensions are commonly distributed as a patch.
See also: Unicode, Chinese input methods for computer
