Finding a house or apartment is fairly straight forward although we recommend a Japanese speaking friend to help you with the process. "Key Money" is still a reality in Japan and must be paid. This tends to be a whole months rent up front and has no other purpose than to say thanks for renting me your place. You will also need a guarantor and there are plenty of companies springing up in Japan to do this for you. A typical cost is around 60,000 to 100,000 Yen (about $600 to $1000).
Global trust networks
This is a good guarantee company located in Tokyo. They are very reasonably priced but be prepared to turn over two years worth of tax returns and estimated proof of income.
real estate agents
Daimaru Trading Co is one of the few real estate agencies in Sendai with a capable English speaking agent available. It is still a good idea to have a Japanese friend in on the process just in case something gets missed.