“Are there specific or correct pitches for notes on the shakuhachi?”
The short answer to this question is both yes and no. In general though, we should all seek to be in harmony with our selves and our instruments, what ever harmony means to us at a given time. Most can agree that playing the basic notes in the regular head position should produce the minor pentatonic scale in both octaves with minimal shift in pitch between octaves. The flute should also produce the correct notes for its length, though this can take time/practice as well. However, most would agree that this is not only a reasonable goal but an essential one.
Note that some shakuhachi, particularly old ones or with old style tuning, may have certain notes which are supposed to be a bit flat or sharp (microntonal). For example, old tuning may have notes that are 25 to 40 cents flat and the 3rd hole is often sharp by as much as 50 cents. These traits can aid in the production of cross-fingered notes and make for a different microtonal mood. The sharp 3rd hole is often compensated for by flattening the pitch slightly. So it’s my opinion that they should not be thought of as “out of tune” in terms of the greater world of shakuhachi.
“What were the pitches used in the old days/Edo period?”
We don’t really know all of the exact microtonal pitches used throughout the Edo period since we don’t have recordings but we do have access to old instruments as I mentioned above and we do know the scale/intervals used for the honkyoku and in other genres of shakuhachi music. This scale is called the Insempo or In scale for short. Some of the notes for this scale on the shakuhachi require flattening of the pitch or meri which is very difficult. Historically, many people have had a somewhat wide range of pitches for these meri notes. For this reason stringed interments in an ensemble with the shakuhachi would tune to the shakuhachi player.
“What about the pitch of meri notes? Should I strive for any specific pitches in my playing?”
When it comes to the pitch of meri notes there’s less consensus. What most everyone can agree on though is that achieving flatter pitches is more difficult. It’s actually physically harder, without a doubt. So it could be said with a fair amount of certainty that playing flatter and deeper is like progressing in exercise which results in more ability. Someone who can jump 10 feet has more jumping capability than someone who can jump 5 feet. So someone who can flatten the pitch of any given note more has more range than someone who cannot. This is also like a painter having access to more colors to paint with. With that said, what colors an artist uses is totally up to them, ideally. What pitches one should strive for is mostly determined by their chosen teacher(s) and or school(s).
“How do you approach pitch as a teacher in your lessons with students? What is your philosophy?”
As a teacher I make it my goal to help people with their goals. Usually, and naturally, students want to sound like their chosen teacher. So often I’m helping people, little by little, get deeper on their meri notes because I play my meri notes on the deep side. However, I consider this a long term goal and only comment on pitch when I know a student is capable of going deeper, if the student requests that I monitor pitch very closely, or if it seems the student is unaware of or has neglected trying to achieve deeper pitches.
In short, once someone has the ability to go deep on meri notes and flatten the pitch to a greater degree I think none would argue that it’s completely up to that individual whether or not they wish to go that deep, or in other words if they actually like the sound of it. Of course it’s also possible, and more common, for someone to not have the ability to flatten the pitch very far and still not prefer the deeper sound, sometimes criticizing people who play deeper or claim that it’s incorrect. On the opposite end, for those that have worked diligently on achieving flatter pitches, there can also be a sense of pride and of being better or more correct than those that play more sharply. Hopefully the reader can see the humor in these situations!
In my personal experience, it’s important to realize that we build preferences mostly based on what we’re exposed to, either first or the most. Take for example someone who doesn’t like a certain foreign food item. They can learn to enjoy that food or cuisine with exposure. If a value judgment is mostly made up of what we’re exposed to more or first then these judgments are largely subjective, holding little reality outside of our thoughts and feelings. So I feel the safest assumption would be that one could get used to or appreciate any pitches. In any case, there’s no need to be dogmatic about pitch. After all, most of what we do on the shakuhachi is solo music.