That wall must go. The same thought nagged Mariko Maruoka every evening while she cooked dinner for her family. The dividing wall that ran between kitchen and dining area served no useful purpose.

"It was kind of dark standing there, and I also felt shut out of what was going on because of it," recalls Maruoka, 40, who lives in a 15-year-old house in central Tokyo with her parents, her husband and their three daughters, who are all in elementary school.

The family usually ate together at a large table in the dining room, where the only other major item of furniture was a capacious cupboard. However, the dining area seemed to have shrunk, too, over the years as the children grew older. "Things had changed for our family since we first built the house, and basically we needed more space," Maruoka says.