But that doesn't mean the idea of living with an unrelated roommate that isn't your boyfriend/girlfriend is unheard of in this country.
Recently the terms シェアハウス ("share house") and ルームシェア ("room share") have gained popularity in Japanese, and some properties targeting and encouraging shared living arrangements are dotting urban areas. Aside from dozens of proprietary sites advertising those properties (just run either of those two terms through Google), a few Craigslist style listing sites are also popping up on the Japanese web where renters can advertise an open room in their home.
One such site is RoomShare net. Many of the ads here are for a Tokyo audience, but the site is not restricted to any one area in Japan. If you're interested in changing up your living environment, inviting someone to stay with you or looking for a place for yourself, take a look at listings for your city here.
Just like at home, though, you'll want to go over fine details with your roommate-to-be. Use common sense. If they are renting, their contract may specify "no roommates" as above, giving you no legal claim to residence if your roommate decides to kick you out or if the landlord finds out and refuses to turn a blind eye.
Check out our next updates on Twitter and Facebook. And if you're looking for info on apartments in Japan, take a look at our past articles on accommodations.