I broke my ni no ito. It came with my shamisen, and I think it was pretty old, so it was really a matter of time. So, I need a replacement. I’ve been looking around on ebay, amazon, and the bachido store, and it seems like nobody uses measurements that make sense. I have some callipers, and I measured my strings to 0.83~0.85mm for the ichi no ito, 0.60~0.64mm for the ni no ito, and 0.38~0.40mm for the san no ito. I don’t know how that corresponds to string gauge. Can someone help me find the strings I need?
Hi Sam!
Never fear, string breakage happens to the best of us. 
Do you know what kind of shamisen you have? This guide can help you identify it - http://bachido.com/overview/shamisen-styles
If you are still unsure, please post a picture of your shamisen and we can check it out. Once identified, I can tell you what strings would be appropriate for your instrument.
Cheers!
Kyle
Thanks for your quick response! My shamisen is a nagauta style.
Another thing I was wondering about is what Tsugaru, jiuta, minyo, etc. mean in terms of strings. When I was looking on Amazon and Rakuten, I noticed that that was how they differentiated their strings. I was wondering if it has something to do with the thickness, but I noticed there were strings of the same thickness that were listed as being for different styles.
Ah, then I’d recommend a simple pack of “Ni no Ito (Tetoron)” (http://bachido.com/store/ito). 
It depends on who you ask. If you are pursuing the nagauta aesthetic, you may want to get silk ni no ito. But if you don’t have a strong preference, I find the Ni no Ito (Tetoron) to work just fine for all styles. Thickness-wise, it’s all pretty close. The ichi no ito thickness is the biggest difference though.
Yeah, I’m not too set on tradition, as long as it’s functional and sounds good. My dou is skinned with calfskin courtesy of Jessica Dowd, which I’m sure is sacrilege to certain purists. But, it suits my needs, and I think it has a nice warm flavor.
It sounds like tetoron is a pretty solid alternative to silk, especially in terms of durability. I think I’ll put in an order right away. Thanks for your help! 
Sounds good man! Jessica does great work. Knowing that she skinned your shamisen, I’m sure it sounds excellent!
Samsan,
I will once again sound the clarion call of nylon monofilament fishing line - cheap, twangy, and easily procured. If one has no objection to tossing tradition to the wind, that is. I use fishing line on my SanXian for the highest string as the traditional twisted silk breaks almost as soon as it is tuned. Plenty of volume and no fears beating on the string for those SanXian-based therapy sessions.
I find banjo strings good in an emergency.
Huh, I hadn’t even thought of using banjo strings, but it makes sense. Banjo and shamisen are similar instruments in terms of register and timbre. The only thing is that they might not come in the right thickness, and it would be hard to know since strings don’t really seem to use a standardized measurement system across instruments. Having the wrong string thickness could cause problems with getting the desired string tension while producing the desired tone. I feel like that could also be a problem with the fishing line, although fishing line does seem to be structurally similar to a shamisen 3rd string.
Thanks for the recommendations, though. I’m definitely open to trying non-standard materials. Would either of you happen to have callipers that you could measure your strings with? I’m curious to know how close in thickness your suggested shamisen string substitutes are to the real deal.
I took some broken SanXian string to the sporting goods shop and bought two cheap small reels of monofilament that seemed about right - one too thick, one just a hair too thick. The heavier worked best, and I have not broken the first replacement yet, so I’m good for string for the rest of my life, plus ready to fish if I ever decide to.
My goodness, Pennysan, I do hope you survived your shamisen emergency intact! It sounds very serious indeed. Good thing you thought of banjo - I tend to think of potable water in an emergency, and would have been lost.
Make sure you keep your lifetimes worth of string out of sunlight,or it will start to deteriorate. I am about to resort to another banjo string,as another string has gone! Cant they feed the silkworms steroids to make the strings stronger?!