12 Bar Blues chord pattern

• 12 bar blues is a is a chord progression that uses just three chords

  
• The chord progression that uses just three chords

  The three chords are played in a repeated pattern.  

  The chord pattern lasts for 12 bars,

  
• A typical Rock n Roll song will use the 12 Bar Blues chord pattern all the way through the song.

  
• the time signature for 12 blues chord pattern is 4/4
• this chord is in

  C major as it flows