TOKYO -- As wealthy domestic and international investors enjoy Japan's real estate boom, young salaried workers are being shut out of a key market for local property investors: Japan's shoebox condominiums, which have traditionally been a source of retirement income for many people. One-room condos, or studios, were once an attractive investment for young professionals, but prices are moving beyond the reach of many, as property values climb, and Japan returns to a "world with rates." The Bank of Japan (BOJ) has begun raising interest rates, thereby pushing up the cost of mortgages.