Shift-jis decoding is actually one of the extensions like cp932?

[johnflux]

Opening a file with "shift-jis" encoding actually opens it with one of the extensions (cp932? shift-jis 2004? Windows-31J? ).

It's not clear what extension it is actually using.

Edit: Bot falsely tagged as 'extensions' because of the title. Dunno how to remove tag.

[bpasero]

VS Code supports a wide range of file encodings. You can see the full list when you click on the lower right status bar where the encoding is shown and then choose to either reopen the file with a specific encoding or save the file with a specific encoding:

There are two options how to configure the encoding for files

Configure the encoding as a setting for all files or files of specific type
We provide a files.encoding setting that you can use to set an encoding for all files. You can also configure this encoding for specific file types, e.g. like this:

"[markdown]": {
    "files.encoding": "utf8"
}

Configure VS Code to automatically detect the encoding when opening files
We provide a files.autoGuessEncoding setting that you can enable to let VS Code detect the encoding of every file automatically. Note that this approach is known to not be accurate in all cases. This guessing of encoding is rather a heuristic that can produce wrong results (that is also why this setting is not enabled by default).

Please also check out issues that are already reported with the files-encoding label: https://github.com/Microsoft/vscode/issues?q=is%3Aopen+is%3Aissue+label%3Afile-encoding

Does this help?