(Delphi uses System.IOUtils)
Different versions of Windows seem to behave differently (e.g. \ and / both work on the English versions)
¥ : Japanese version
₩ : Korean version
While the ₩ and ¥ characters are shown as directory separator symbols in the respective Korean and Japanese windows versions, they are only how those versions of Windows represent the same Unicode code point U+005c as a glyph. The underlying code point for backslash is still the same across English Windows and the Japanese and Korean windows versions.
Also, I don’t know of any Windows API function that gets you the system’s path separator, but you can rely on it being \ in all circumstances.
Note File I/O functions in the Windows API convert “/” to “\” as part of converting the name to an NT-style name, except when using the “\?\” prefix as detailed in the following sections.