I want to know the answer to the following question:
What kind of mappings must be provided between characters in existing legacy character sets and those in Unicode?
All the background I'm provided with is that "Lack of consistency in various mappings between earlier Japanese encodings such as Shift-JIS or EUC-JP and Unicode led to round-trip format conversion mismatches, particularly the mapping of the character JIS X 0208 '～'". Is that enough to answer the question?
Answer: no