Justin's Completely Free Jazz Guitar Lessons. This is Lesson JA-029.
In this guitar lesson we look at the jazz theory concept of using a diminished chord as a 7b9 chord. You should probably check out the jazz lesson series on the web site if you are getting stuck with the concepts here - and there are notes about this lesson there too - and I think it is easier to read some of this stuff than listen - helps you understand it faster, imho.
It's kind of a chord substitution (you'll often see it called that) but I think it is more just using a shape a different way, it's not really a substitution in the proper sense of the word... more on the web site about that!
Find the related course notes on the following link:
Taught by Justin Sandercoe.
Full support at the justinguitar web site where you will find hundreds of lessons on a wide range of subjects, and all the scales and chords that you will ever need! There is a great forum too to get help, no matter what the problem.
And it is all totally free, no bull. No sample lessons, no memberships, no free ebook. Just tons of great lessons :)
To get help with this lesson (and for further info and tabs), find the Lesson ID in the video title (like ST-667 or whatever) and then look it up on the Lesson Index page of justinguitar.com
Have fun :)