Lucky, lucky. You’re a skin and some strings away from playable.
That shamisen was purchased or last skinned at Takahashi Wagakkiya, a Tokyo based store. The last skinning was conducted in October (on the 29th) of the 5th year of the Showa period. So it’s an old girl!
It was previously skinned with dog leather on both sides.
The customer’s name was 尾山 it seems. Although don’t quote me on that, the first kanji is written very casually.
There is no azuma or en sawari. The neck is mitsuori and has a nice hatomune.
The wood is dark enough to be kouki, but I would be hesitant to call it such without viewing the unstained wood at the joint. Old kouki is usually very black, so this may be something else.
The koma is very wide and probably very tall. It might be for hauta, kouta, or jiuta. That said, given the presence of a bachi, I’m somewhat doubtful of kouta, and given the size of the bachi jiuta also seems unlikely.
If you can show me a closer picture I might be able to better id it.
The bachi appears to be wood.
The itomaki are the star-shaped varietal, which I’m personally fond of.
Please flip over the doukake and look for any markings. There will likely be a size mark. This will tell us more about its classing.
If you are able, take a measure to the width of the neck near the tenjin and near the dou.