Azumaso is a Ryokan with hertitage, dating back 100 years. There is some patina in the main building, but the property is well maintained. While there are two gender-separated public onsen (24h available, one open-air, one indoors), I recommend you to stay in the new wing and ideally to choose a room with private open-air onsen. These are large rooms with a very nice layout, such as a seperate dining room. Dinner and breakfast are served in your room. Azumaso has a decent selection of Sake and offers four different tasting sets, with three cups each.
While Azumaso is not one of the super luxurious Ryokan (i.e. no staff member is running towards your car as soon as you arrive, there is no bar area nor restaurant), all staff members were friendly, helpful and we had a very pleasant stay and enjoyed the hospitality. I would choose Azumaso again.

We were a little worried about our booking at Azumaso, mainly because the pricing was considerably less than other luxury ryokan. As readers may know, in Japan, generally, the higher the price, the better the experience; the lower the price, the worse the experience. BUT, we did not have to worry!

Our room at Azumaso was huge. We reserved a room called "Dream," and it was a dream! The ryokan had two large tatami rooms, one that served as a sitting room and the other that served as a bedroom. In addition, it had a dining room that let people unused to a Japanese dining experience to sit at a "normal" table with chairs. We were impressed that the person who made up our bed was able to put the futon together and extend the futon to deal with a tall person. Very nice.

This room came with its own private hot spring bath. It was a cedar tub bath which was excellent for two people. The water was authentic hot spring water and the temperature was piping hot. We needed to seriously cool down the water in the morning before we stepped into the bath. We never had the desire to try another bath as our bath was decadently pleasurable -- you could soak outdoors in a very hot bath and then totter off to bed.

The food, served in our room, was top notch. We could not have been more pleased. And, the portions were immense! Our quibble was with the service. The waitresses seemed to be under immense pressure to serve and leave -- in our stay, it seemed like we were being rushed. If you are eating in your own room, why rush the experience? While the waitresses were friendly and efficient, we believe that Azumaso had too few waitresses, and so the waitresses had a lot of pressure to handle customers quickly.

There is not view, as this ryokan is in the hotel section of Tendo city. But, we had a pleasant garden view, a very nice bath (fully outdoors), and loads of space. In addition, our room was quite bright.

We stayed at Azumaso for two nights.
I would write this review if I had been helped but no reaction came from the reception when I complained about the noise. It had been loud the first night - we said nothing and hoped for a better second night, but it was even worse, drunken Japanese roared at the Rotenburo until late and started again at 3.30 at night. I rang the reception - in vain - they understood clearly but noise went on. At 6.30 the neigbor started to watch TV ( must have been deaf) I knocked at the wall - no reaction. Again I rang the reception, again they clearly understood my concern, again no reaction. This is a typical Japanese attitude, if they do not know what to do, or di not want to do anything, they just ignore the situation thus pretending that there is no problem. And in the end, we were " just" foreigners. I had never been treated in such an ignorant way.
Additionally the ryokan is scrappy, carpet and furniture must be from the 50ies or 60ies. The place needs renovation.
Tendo itself has nothing special to offer except for its proximity to Yamadera.
If I had to choose again, I'ld rather prefer Yamagata for an overnight stay, though a bit further away from beautiful Yamadera.