Capsule Hotel 310

It's a mixed hotel with sleeping capsules on the 5th floor and shared sleeping space without walls and curtains on the 4th floor. Onsen is on the 2nd. Very old, but clean and has sauna. Consider it as a bonus rather than proper onsen.
Capsule space is pretty common. Length of each capsule is around 195 cm. Not so easy to climb on the 2nd level (I didn't care about that). Wi-Fi is unreachable in some capsules far from entrance.
Additionally it's worth to mention snoring issue. Not a direct responsibility of a hotel. But I do think people who snores has to sleep separately. It was too much of annoying sound in that hotel. It went easily through earplugs.

Be sure to check that you actually booked the capsule hotel package instead of the share space package. I didn't realize that it was the share space package and had to sleep in a very bright room/floor with a bunch of snoring uncs and grandpas. My mistake. Bring earplugs and a eyemask. Service was great though, very accommodating. There's a "restaurant" inside, though I didnt bother getting food there since theres better food just right outside.
Theres a communal onsen too, though you have to get fully naked, as per Japanese tradition. Onsen is well equipped, with a Sauna, shower space and hot tubs.
Also, NO GIRLS. 2 towels and a pair of pajamas is provided daily, along with free razors and toothbrushes in their designated areas.

This is an all-male accommodation facility with a cheap price of 3, 500 yen per night. The sleeping together plan allows you to spend time with a large number of people in the napping room. The facilities are designed in an ancient Roman style, and the lobby and public baths are clean and spacious. The large baths are equipped with large bathtubs and saunas, while the rest rooms on the third floor and the nap rooms on the fourth floor offer basic accommodation, with pillows and blankets provided.