The direct answer to the question is that you can do it either way. As long as all the people playing the tune are on the same page; changing chords at the same time. You can play the V7 chord for both measures 9 & 10. Or you can move to the IV chord for the 10th measure.

For that matter you could play measure 2 as a IV chord also. Many blues tunes do that one. The point is that you can do it anyway you want. I created that tutorial specifically like that so beginners wouldn't have to deal with too many chord changes. The only changes they have to negotiate are between E5 and A5, and then, E5 and a simple B7. I methodically try to keep what the student has to learn in beginner lessons or tuts under a certain amount. Otherwise it's counterproductive, conceptually & physically.

There are other tuts I did that have the IV chord in the 10th measure. And many other variations for more advanced practicing. While I am on the topic ( :rolleyes: "Here he goes again..."), I got into a discussion about 12-bar blues the other day with a fellow musician.

Most western music from baroque and classical on up through to jazz and pop tunes are more frequently units of 8 measures. So it's more usual to see phrases, sections, phrases, verses, choruses, and so on in 8, 16, 32 measure units. The 12 bar blues is a bit of an anomoly in popular music in this respect.

To those used to hearing and playing it of course it sounds just fine. But there have been many times I've played gigs with guys that are fine, skilled musicians but not accustomed to the 12 bar standard. It was alternately frustrating and comic to be just cruising along through a set and have one of these guys constantly fumbling around missing the turnaround. It seemed like it always happened "too quickly!" for them. :p

In fact at one gig it got so bad that after the bassist goofed up like the 5th or 6th blues tunes of the night I just told him to stop playing on them. Just turn down your volume and play air-bass or take a break. And I played the bass parts and the chords ala Joe Pass. Which was good practice for me.

Anyway, you can play it either way. Just make sure everyone knows exactly which way before you count it off. ;)