How does vim break 1 line into 2 lines under normal mode, by 1 type?

Question

Under normal mode, to merge 2 lines, we can press J. But how to break one line (somewhere in the middle) into 2 lines? Now I can only press i to enter insert mode and press <CR>.

Is there a command under normal mode, one type to do this?

Answer 1

No there isn't. However you can map it like nnoremap K i<CR><esc>