Tongue block switching

Sorry for the delay in replying, I've been traveling with poor internet access and am getting caught up.

The main advantage of being able to corner switch (alternate betwen the right and left corners of your mouth while tongue blocking) is being able to move smoothly, cleanly, and quickly between notes that are several holes away from each other.

Let's say you have a mine where if you go to the right, you get gold. It's easy to dig and everyone follows that vein, and everybody says "that's a gold mine." But let's say you go to the left and ithat vein has diamonds. But it's harder to dig there and  so nobody does it and if you ask whether it' a diamond mine, people give you a funny look and say, "Naw, that's a gold mine! Ain't no diamonds coming out of that hole in the ground."

Corner switching in the bues is a little like that. It's seldom heard in blues, not because it doesn't fit but because nobody goes the slightly harder route of learning it and using it.

Except Little Walter.

Walter sometimes used corner swtiching as part of a melody line, but he was more likely to use it to produce a quick alternating back-and-forth between two non-nighbpring notes, sort of like a warble. You can hear him doing it in the intro to "Oh Baby (You're Going to Mss Me When I'm Gone)" and also behind Muddy in the second verse of "I'm Ready." Walter was more ikely to move his tongue from side to side on the harmonica than on and off, so corner switching was just a refinement of what I call a rake - where you swish your tongue left to right, back and forth quickly over a chord.

Melodies that rapidly alternate back and forth between a high and a low note are naturals for corner switching. A lot of classical melodies and fiddle tunes do that, and some jazz tunes, like Take the A Train. While you won't hear a lot of that in blues harmonica, you'll hear it in guitar and piano lines if you listen for it. On harmonica, those lines are awkward with a single point embouchure (pucker or right-ony tongue block). But corner switching makes them easier to play and thus can open up new posibilities.