The first of the 94x94 codes was the Japanese standard JIS C 6226-1978 (Old-JIS). This was re-arranged to accommodate the 1981 Jouyou Kanji list (all of which are in level 1), resulting in JIS C 6226-1983 (New-JIS, renamed JIS X0208-1983 in 1987). Two kanji have since been added to level 2, giving the current JIS X0208-1990:
[This seems an appropriate place to mention JIS X0201-1976 (called JIS C 6220 until 1987), an 8-bit code. Its left half (JIS-Roman) is the Japanese national variant of ISO 646 and differs from US-ASCII only in having a yen symbol in place of the backslash (5C) and an overline in place of the tilde (7E). Its right half (A1-DF) comprises Japanese punctuation and katakana.]
An extension is defined by JIS X0212-1990:
The non-kanji parts of JIS X0208-1990 and JIS X0212-1990 occupy disjoint code ranges.