In this lesson, we'll be looking at our first song, which is the classic 12-bar blues progression that we've all heard so many times over the years. This chart is a "skeleton" chart, only featuring the minimal information. For this version of the 12-bar blues, we'll be playing in the key of A. Note that all of the chords represented are 7th (dominant 7th) chords. The song is in 4 or 4/4 time, which means that each chord has a duration of 4 beats (whether you're holding the chord out, strumming, or playing boogie-woogie licks). For the chord at the end of the song in the “diamond," play that chord on the “1” of the beat and hold it out for the rest of the measure. Anytime you see a diamond like this in the NNS that means to hold it out for the whole measure. Typically, if this is a band performance, the rest of the band will be doing the same.