[saidajigumi]

    :vsplit .

On this point, it's worth noting that users of the NERDTree plugin[1] can set it to work with the above style of use as well:

    " Replace netrw with secondary NERDTree
    let NERDTreeHijackNetrw=1

[1] https://github.com/scrooloose/nerdtree/

[Davertron]

Thanks for this, I was searching for this exact thing the other day and couldn't find it.