Chinese, Korean, and Japanese names are based on Chinese characters or ideographs, usually 3
China, Korea - the surname is 1 syllable/iedograph
Japan - the surname is multiple syllables/ideographs
Vietnamese names often have diacritics (acute and grave accent, circuflex on "a", "e", "o", tilde, a dot, etc.; also "o" with a hook, a with a breve accent over it, "d" with a bar across the top and diptongs. Examples: Cao, Ngo (circumflex over "o"), Dao (D with a crossbar, grave accent of "a", Duong ("u" and "o" with a hook). The Vietnamese do their names in this order: Last, Middle First; or surname "Thi" (for women) or "Van" (for men) and end with a given name. On authority records, put the comma after the first word which is the last name, create a 4XX Words in order as given
Only CJK are transliterated characters. Vietnamese uses the Roman alphabet.
If the name is multi-syllabic and ends in a vowel, it is likely to be Japanase, e.g., Hirohito, Miyako, Shuichi Kasaka, Shinpei Kusano.
If the name consists of 3 syllables, either written separately, or with two connected or separated by a hyphen, it is likely to be Chinese.
The hypenated or connected vowels should be considered the forenames in Chinese. However, watch for married women's names where they might have hyphenated their husbands surname with their own surname.
Surnames are usually one syllable, so if names are multiples with hyphens, it is probably not a surname.
In materials published in the Asian countries, the surname is first. Western publications often move the surname to the end. Look for hyphenated or combined given names.
If you are establishing a name with a CJK book in hand, usually you are to use the hyphen between the first and second character/ideograph with the second one in lower case for Chinese or Korean, but not Japanese.