Even with a hard case do you put your shamisen in a soft cover? Do you wipe it down after every use? What bag goes in it to prevent moisture? Ive seen shamisen players who remove the bridge and strings after every session… what are some guidelines on this?
Pics would be a great help and exactly what types of clothes, bags etc are you using?
Hi Lissie!
Great questions! It really depends on the person. While I always wrap my shamisen in a cloth bag (nagafukuro) even in a hard case out of habit, several of my professional shamisen friends in Japan simply put it in the case without the bag. While it’s great for keeping dust off the shamisen outside of a case, there’s no practical reason for it. I do so out of habit and mental discipline, although often ask myself, “Why do I do this??” 
Wiping down after use is a good idea, as oil and grime from the hands/fingers can build up on the sao. (Any microfiber cloth or even a soft shirt can work.) Removing the koma is also good, as it relieves tension from the strings and the koma, so both will last longer.
I have a little article on basic care written here. Nothing too special but it might be useful. 
- Caring for your Shamisen
Thats very useful, thank you! How do you avoid letting the notch in your fingernail too deep? Just manicuring? Ie. Keep it trimmed short or filing it back some when it gets “deep”?
How should I be storing the koma? I have a storage spave in my case but its HUGE compared to the space.
Yep, just trimming/filing is all you need to do.
Actually, a great box for koma are lipstick cases. Koto players often use them to store their picks, and a few fellow shamisen friends use them for their koma (they got me started using it too). The size is perfect and the snap style lip is so easy to open/close.
Whaaaa? Mind blown. Makes sense. Do you know about the bag (assuming) for humidity that people use to store their shamisen?