unbar vs unfasten

unbar

verb
  • To remove an impediment that obstructs the passage of (someone or something). 

  • To remove a prohibition. 

  • To unlock or unbolt a door that had been locked or bolted with a bar. 

unfasten

verb
  • To detach from any connecting agency or link; to disconnect. 

  • To come unloosed or untied. 

How often have the words unbar and unfasten occurred in a corpus of books? (source: Google Ngram Viewer )