Silk & Tetoron
Some people use tetoron on their second or third strings, but not all. Popular load outs include
Tetoron is a kind of polyester and it’s very strong, but lends a blunt, thunky sound.
Niagari is a relative tuning with many possibilities, but CGC is among the most common. As long as your first string is middle-c, you shouldn’t be pushing the strings too hard here.
I asked because I’ve been known to use my nail to create interesting hajiki sounds before it was murder on the string.
Tsugaru music doesn’t require a tsugaru shamisen by any means, it’s a method of play. If you’re using a different kind of shamisen, you can get the same vibe as tsugaru (even if the sound is rather different). I wouldn’t say you fully mimic the sound of a modern, full size tsugaru. Physics are just at odds with that - but the essence of the music can be managed with anything.
Anyway, I see, I see. Very honestly, I think a string a month isn’t bad for silk seconds. However:
I want you to look in a few places on your shamisen and koma.
Check for sharp points at the kamigoma (knut), and for any chipping on your bachi, or sharp edges on your koma all of these can accelerate how fast strings pop.
Beyond that, you can lower the tension after playing… But very honestly, you’re not playing at such a high tuning. I don’t think it will help over much.
It is also possible that the strings you have are older, which will mean they’re a bit more brittle than usual. Silk is a natural materials after all!