It was said of the California Gold Rush of the mid-19th century that the ones who made the money were those who sold the shovels. Today's shovel sellers in Tokyo are the service providers, agents and brokers eager to entice clients with tales of gold in the hills.

Recently there has been a spate of real estate investment seminars targeting average salarymen and expats in Tokyo. A common opportunity presented is the whole-apartment-building investment, and the idea is simple: Find a building producing a healthy rental yield and organize financing from a willing institution.

Many banks have relaxed their lending requirements to enable anyone with a salary of over ¥7 million and in full-time employment to get an investment mortgage. Throw in permanent residency, a Japanese spouse and some capital, and mortgages of over 10 times an applicant's salary covering 90-100 percent of the property value at a fairly modest interest rates over 30-plus years can be easily arranged. Create a spreadsheet and make sure your rental yield is comfortably higher than your mortgage repayments and expenses and, hey presto, a cash-flow-positive investment, using little or none of your own capital. Sound too good to be true? Perhaps it is.