[Answer]
In Japan, most of the housing rental contracts require a guarantor to
cosign a rental agreement to ensure compensation for any damage done by
a tenant who violates a contract. When a guarantor signs a rental agreement for
another person he/she is legally bound to pay any amounts owed should the
tenant incur damages to the landlord. Therefore, finding a guarantor is not
easy for foreigners who have not stayed in Japan long enough to find somebody
who is willing to shoulder the responsibility for them. Try some apartment
complexes intended for foreigners or guesthouses, weekly apartments since some
of them do not require guarantors. Also you can ask if can substitute providing
a guarantor by paying rent by credit card since some real estate agencies institute
such system for those who cannot find guarantors themselves. You have to pay
handling fees if you use this system. Some landlords and realtors allow a
tenant to use a rent guaranteeing system or proxy guarantor system. Check their
credibility and business operations before you decide to use their services to
avoid any pitfalls.