Koma Angle

Playing/Techniques
#1

Most of the time I see the koma placed perpendicular to the strings, but every now and then I see it at an angle. Usually the lower end is towards the bottom of the shamisen. Does anyone know if there’s a reason for this?

Changing the angle would bring the strings closer together as they reach the koma. They would also sit differently in the koma which might produce different tones for each string. I noticed the angle lines up with the wrist’s natural swinging/striking motion so I’m not sure if that’s a factor. Just a few ideas that come to mind.

#2

Hi. I think that this position gives both crisper treble and deeper bass (as closer to the center of the dou, the bottom end of the koma has a more important vibration and closer to the edge, the lower end has a limited vibration).

#3

It may also allow for better intonation. This is more practical on fretted instruments, though. I think on Shamisen, it would cause the lower string to be more of a stretch for short stubby fingers like mine.

#4

It happens accidentally for me after a particularly savage session.
I’ve never had any of my (highly respected) teachers arrange the koma that way, so I’ve never bothered. However I’ve seen some do it at the tournaments.

#5

On guitars, the saddle (the guitar version of the koma) is angled to deal with the the different gauge strings needing slightly longer lengths to have correct intonation with the frets. (It gets a bit more complicated, hence bridge inventions like the Tune-O-Matic with tiny nuts to adjust the exact length of each string.)

OK - the weird part: on guitars, the lower, fatter strings are a bit longer. So, shamisen players who angle the koma the opposite direction are (theoretically) making the intonation worse.

Now, since the shamisen is fretless and intonation is finger placement+muscle memory+ear, there should be no issues of intonation: a player has full control over pitch. Koma angle is just an issue of taste and habit viewed this way.

Regarding sweet spot on the skin, that would change with each pitch, and only hold true for harmonics of a given pitch (look up Chladni’s figures on Youtube for some cool examples). So, angling might indeed find sweet spots for the three strings, as Patricksan suggests. String tension is less for the thinner strings, and so Grantsan finds his koma slipping after he beats on his strings - this also makes sense.

One could get pragmatic and try angling the koma this way and that and listen for differences. Recording the experiments would give hard data; notes could be sonogrammed to explore just what is happening in a more objective way.

Or one could just play and enjoy. But, Joelsan, it is a good observation and an excellent question.

© 2020 Kyle Abbott