Gansomuro hut is on the 8th station, of the Yoshida trail, while climbing Mt Fuji. While searching for more information about the huts, I realized how little English information is available about the huts. Also, I read on many sites that it is very difficult to book the huts, if you dont speak Japanese, etc. However, that is not entirely true. I am not sure, if it was always like this, but this summer when we were planning our climb on Mt Fuji we found at least 3 huts with English websites and allowing bookings in English via email.
The hut has communal beds, so when you sleep you can easily touch the other person sleeping next to you. You are literally packed like sardines. However, it does not matter as you will spend a very short time there anyways. Most of the people wake up around 2am to start their climb to the summit, and to see the sunrise from the summit.
Gansomuro is located at 3250m. I saw many people getting sick in the night due to the high altitude. Even my wife was sick.
They serve you dinner, it is first come first serve. As the dining area is quite small. They give time slots to the people, as they come in.
The kitchen at Gansomuro
The food was surprisingly tasty. They have curry with rice, along with a fried piece of meat.
Conclusion
It is a decent place to spend the night. It was clean and the service was great. Of course, for the money they charge you you would expect fancy place to stay, but remember you are spending the night at 3250m. Do not expect luxury, and just keep in mind that you will be spending just a few hours here and you will be fine.