Split notes

I am by no means a pro player but I know exactly what you're talking about as I used to have that happen from time to time when I started. I imagine it's just down to your embochure (sp?) and the longer you play the less that will happen. I've been playing a while (though compared to some of the people on here I've been playing 5 minutes!) and in my experience I've yet to come across a technique which requires otsu and kan at the same time...

No sounds are always "no-no's" but you need to know-know when to use them.

Or else:

Best to go for the straight notes at first.

Good advice. Many thanks 

A more detailed answer might be that experienced players often choose to introduce harmonics and noise into their tone for effect. But they can also expertly control pure tones in otsu and kan.

I always looked at it sort of like a race driver taking the corners so fast the car is sliding some and he has to fight the wheel. The hands of a skilled professional can keep the car in control and do this around every turn, a lesser skilled driver would crash soon. With shakuhachi, letting the tone stop is equivalent to crashing. It's fine to practice going fast in the car, but since you don't want to be practicing crashing, you start out at a normal speed and work up until you get a feel for it. Same with shakuhachi, start out with a nice straight tone you can hold, and eventually work your way to adding wind and harmonics to those notes with as little "crashing" along the way as possible.

Very experienced, contemporary players use an extended technique call multiphonic blowing. This produces more than two notes simultaneously. You most likely will not use this technique with older, traditional styles of playing, but it can be very useful for contemporary approaches to playing. Akikazu Nakamura's honkyoku is full of multiphonics.



Precisely

I have a good knowledge of multiphonics through overtone singing. I'm not bad at singing the bass Kagyra styles especially.
But I shall stick with the search for a 'pure' sound first. I am finding that if I play whilst standing I can get more control of the airflow and the 'clean' tone is a little more evident.
Onwards, and once again thank you for your wisdom.

By all means chime in if I am off, but isn't this muraiki? i.e. both octaves at once.

Paul, sounds to me like you are doing well. Soon enough you will be rid of this, and then later, will work hard to try and be able to do it again (but on command, like Brian was saying)

If you get kan when you try to blow otsu notes, then this most probably occurs because you are blowing too hard. Otsu requires a little less speed in the airflow than kan. Most beginners try to get notes by blowing harder, but that is not necessary - not even in kan. When playing kan you should make the hole in your lips narrower and push basically the same amount of air through as otsu. When doing this you will automatically have a faster airflow.
If you try to play kan and you get a mix of otsu notes, then your embouchure is probably not settled yet and have a little too loose or relaxed lips, and most probably you have a little too slow in the airflow.

Also the place of the "sweet spot" that produces sound is slightly different when blowing otsu and kan. I find that the kan spot is like a millimeterr or the like above the spot for otsu.

So there are 3 things to be in control of a "clean" otsu and kan:

1. speed of air
2. tightness of lips/embouchure + shape of the hole in lips
3. the direction of breath/the sweet spot for producing sound

And as the others have already said, in the beginning you always try to get as clean notes as possible. When you are in control of your sound production and pitch, you can add the fun stuff that makes shakuhachi music become alive and interesting!

Good luck!

Lorka, thank you.
Kiku, thank you for taking the time to offer your wisdom and experience
I will contact you directly so that I can have a proper lesson with you, when you are in London and when of course it's convenient for you.
Many thanks both of you.