Capsule hotels in Japan are very similar, but they rent nightly as other hotels do. The capsules typically have a shade that acts as a non-locking door, which means there is privacy but not sound isolation. Each floor has keys, so not just anyone can wander in and look at your stuff while you're out. Most offer female-only floors. Some have capsules big enough to store a suitcase under the bed. Others have lockers on a separate floor.

Some places have gym-style showers, or even common bath areas. Some have showers with locking doors, and the facilities can be nicer than many regular hotel bathrooms.

In the places I've stayed, the common areas were universally excellent. Comfy couches and tables for working; cozy nooks for reading; ample kitchens; console video-game libraries. One place had round-the-clock curry and rice in the kitchen, and if you've had Japanese curry you know what a treat that is.

If you're in the right mindset, staying in a capsule hotel in Japan can be a great experience. But bring earplugs; you can be sure that someone on your floor snores.