SCSU
From Just Solve the File Format Problem
SCSU (Standard Compression Scheme for Unicode) is a Unicode character encoding. It is designed for small size, especially when encoding code points that are mostly from the same language. Its main drawback is that it is very stateful.
SCSU blurs the line between a character encoding and a compression scheme. For one thing, there are usually multiple valid ways to encode a given string, and it may be difficult to find the smallest one. It is registered with IANA as a character encoding.
See also BOCU-1, to which it is sometimes compared.
