Shakuhachi bore sizes: wide, medium, and narrow – a ratio of volume to length

You may have heard that shakuhachi can have differing bore sizes for a particular length or key, such as 1.8 D. For instance, a shakuhachi in the key of D can have a “wide”, “medium”, or “narrow” bore and shades in between for that matter. With that said, we must first understand that “wide” doesn’t simply mean “wide mouth” or a wide top inner diameter. Rather, we’re talking about the total inner volume of the bore in relation to the length (inner volume is measured by how much water a shakuhachi can hold). Therefore, when we say “wide bore” and so on, it implies in relation to the length.

Wide bore shakuhachi

Wide bore shakuhachi have a lower bass sound (there are less overtones in the sound). We could say that they have more bass and less treble. They require more effort to resonate, especially in Kan the 2nd register. Which is to say, they take more breath and effort to play than medium bore and narrow bore shakuhachi. They truly favor Otsu the 1st register with Kan the 2nd sounding smaller and weaker by contrast. If we drop the ratio too low we’ll actually begin losing notes in Kan altogether. We can even push it so low as to only have access to Otsu or begin to lose notes in Otsu as well.

Clearly, wide bore shakuhachi are for those that love bass. The tone in Otsu tends to resonant more deeply and the player can feel it more so than hear it. However, in recordings and for people at a distance of about 5 ft from the player this feeling of the bass is lost unless the audio levels are well adjusted and if amplification can deliver enough bass. In other words, with wide bore shakuhachi being played live and without micing and amplification one needs to be close enough to them in order to feel their bass and truly appreciate them. What most often comes across in records and for those at a distance is simply the sounds of struggling with a wide bore shakuhachi which, as we established, will be more difficult to play (how one finds this sound is a matter of taste of course).

Wide bore shakuhachi tend to want to produce muraiki more easily as well; the rough, tumbling, airy breath-technique. Lastly, finger hole size is also in relation to bore size, which is to say that an 11 mm hole on a wide bore shakuhachi is acoustically much smaller/quieter than an 11 mm hole on a narrow bore shakuhachi. This basically just means that wide bore shakuhachi will sound like they have smaller, stuffier, quieter finger holes. People tend to describe the sound of wide bore shakuhachi as being “bassy”, “natural”, “breathy”, “deep”, “nasally”, “rough”, “fuzzy”, and so on.

Medium bore shakuhachi

Next, medium bore shakuhachi will have the greatest range in Otsu and Kan, the primary 1st and 2nd registers of the shakuhachi. Essentially, they can have the greatest flexibility and balance between Otsu and Kan. This is the essence of shakuhachi. With that said, we shouldn’t conflate this with them being subjectively the most ideal shakuhachi. For example, because they’re in the middle, and thus not at an extreme, some people may find them boring, not bold enough, or “lukewarm”; neither “bassy” enough like wide bore shakuhachi nor “brassy” enough like narrow bore shakuhachi. People tend to describe medium bore shakuhachi as having the most “warm”, “woody”, “classic” sound or tone color.

Narrow bore shakuhachi

Lastly, narrow bore shakuhachi tend to be those with human-made bores, aka Jiari or Jinuri and ‘cast-bore’ shakuhachi (there are of course narrow bore Jinashi and Jimori natural bamboo bore shakuhachi as well but they tend to be less common). Narrow bore shakuhachi give us access to more 3rd register Dai Kan notes, however, this also means losing range in the first two registers Otsu and Kan. There is no way around this. For example, if we keep constricting the bore we’ll get a “dog whistle” with a register higher than what the human ear can hear.

Narrow bore shakuhachi will have a more complex, overtone-rich sound which we tend to describe as having higher treble. Interestingly, people also consider such a sound as being more “musical” or “human” and less “naturally occurring” (certainly a philosophical quagmire which I will sidestep). I’ve also heard people describe narrow bore shakuhachi as being “brassy”, “cutting”, “metallic”, “crystalline”, and even “electric”. Lastly, narrow bore shakuhachi will be easier to blow loudly, however, this can also make them feel testy or overly sensitive for some players or situations.