9 public onsens in Shibu Onsen + tattoos

I am visiting Japan for the first time in November from the US and would love to experience 1-2 nights in a rural onsen town. Shibu Onsen looks lovely, but I can't tell if the 9 public onsens accept people with tattoos. My boyfriend has several large tattoos that aren't feasible to bandage or cover up.

Does anyone know if the 9 public onsens in Shibu Onsen accept people with tattoos?

If not, are there any other onsen town recommendations for people with tattoos?

Thanks!

Does anyone know if the 9 public onsens in Shibu Onsen accept people with tattoos?

I tried only two of them, they were virtually private baths, you got the key and you locked the door while having the bath. Who is to know you are with tattoos?

they were virtually private baths

No, such an assumption cannot be made. Sometimes you may happen to be the only users, but generally they are public baths to be be shared by everybody.

you got the key and you locked the door while having the bath.

No, you are not supposed to lock the door while you are having a bath! Such is absolutely unacceptable behavior.

As for the tattoos, I am afraid I was not able to find any official information about it.

No, such an assumption cannot be made

It was not an " assumption". I merely tried to share my personal experience with the two I visited. They were small, barely enough for two people. I do not know the other seven, could be bigger ....
This is not an isolated case, I have experienced a same situation in other public bathhouses; once in Kumano area, the other was in Kyushu ; In these two occasions I had to wait for others to finish.

No, you are not supposed to lock the door while you are having a bath! Such is absolutely unacceptable behavior.

No, you're supposed to lock it. Anyone else wishing to enter will have a key of their own