How do I open a new empty buffer in a horizontal split without opening any file?

Explanation

<C-w>n creates a new empty buffer and opens it in a horizontal split above the current window. The new buffer has no name and no contents — it is a blank scratch pad ready for you to type into or paste content from registers and shell commands.

How it works

• <C-w> — the window command prefix
• n — new empty buffer in a split
• The new window is placed above the current window and receives focus
• The buffer is unnamed ([No Name]) until you write it with :w filename
• The equivalent Ex command is :new (horizontal split) or :vnew (vertical split)

Example

You want a quick scratch space to paste and reorganize yanked lines:

<C-w>n          " open empty split
"0p             " paste last yanked text into the scratch buffer
Go              " append more content
:w notes.txt    " save when you are done

Tips

• For a vertical empty split, use :vnew (there is no direct <C-w> shortcut)
• To open a specific file in a new split, use :new filename or :split filename
• The scratch buffer is not associated with any file on disk — closing it without saving discards the content (Vim will warn you if hidden is not set)
• Combine with :r !command to capture shell output into the new buffer:

  <C-w>n
  :r !git log --oneline -20