Mujitsu and Tairaku's Shakuhachi BBQ

More newbie type questions.....

Okay, is it just me, or is there some sort of in-between kind of an octave between the first and second that you hit just before the note jumps to the second octave?  I will try to be more specific.

When I am mucking about with embrochure and air pressure in the first octave and increasing it to the point where it would go to the second I often (and usually by accident) seem to hit this sound which is not really first octave, and not really second, but something in between.  It has a an odd, somewhat unnerving, but not unpleasant sound to it.  If I am very relaxed (lying on the couch playing) I can sometimes stay in this in-between zone for awhile and experiement with it.  I should add that I am using the Yuu Shakuhachi with this.  It feels to me like there are some secretive sounds hiding between the octaves, wating to be found.

When I use my new 2.7 Hocchiku (which I am less used to, or comfortable with at the moment--- but like more) I get a different effect.  As the Ro note starts to move toward the second octave it starts to do this weird trembling/pulsing/vibrating effect, which is really wonderful.  Again, I tend to get it not so much by will, but by accident/experiement.  What this is, I have no idea, though it seems to happen when I am trying to practive sasa buki, something I recently started thanks to the kind advice of Shaman141 (sean), and Perry. 

Well, I dont know if an in-between octave exists, or I am doing something funny, or what.  But I like that the shakuhachi can produce such a varied and peculiar sonic range.  These instuments continue to enchant, impress, and humble me.  There is so much capability for expression. 

As a funny sidetrack I will give one example before I go.  There is this weird effect that  I get when I do the following.  Close all finger holes, but keep the thumb/back hole open, and then blow.  While blowing, rapidly open and close the bottom hole of the flute, by the root (ring finer, right hand).  If you do this while rising and lowering the volume it creates this "double flute" bird like sound that is very strange.  I'm sure you all know it.  For some reason my (very shakuhachi tolerant) girlfriend always seems to love that sound.  It is more like an "effect" than a note, or a sound, really.  But it is fun to experiment with.  Just one among many examples of how the shakuhachi can create unique sonic expressions.