If you apply the preceding rule to conversion from one double-byte code page to another, you conclude that a conversion is valid if the source code page is a subset of the target code page. The double-byte to double-byte conversions that appear in the following table are valid.

Table 1. Valid double-byte to double-byte code-page conversions
Conversion Comment
SHIFT-JIS to EUCJISEUCJIS to SHIFT-JIS SHIFT-JIS and EUCJIS contain the same symbols
KSC5601 to CP949 KSC5601 is a subset of CP949
BIG-5 to CP950 BIG-5 is a subset of CP950

You cannot convert from CP949 to KSC5601, both code pages for Korean, because CP949 contains many characters that KSC5601 does not.