The mado no ie ("window house") prefabricated house was developed from the concept of building houses around people's lifestyles. A key element in this example of a house designed around-and designed to enrich-the owners' lives is the windows. Windows are initially links between the inside and outside of the home, apertures that bring light in. But ultimately, windows frame views of the world shared among family members, and they nurture growing minds that enjoy these shared perspectives. In Japan, signs of seasonal changes are appreciated as scenery framed by windows. Windows in the "window house" can be freely positioned to suit owners' aesthetic preferences, which reflects the developers' regard for people's freedom in building these links with the outside world. And just as owners can choose where to let light in, square cutouts in internal walls are the simplest way to frame scenes of families linked by communication.

During arts movements of the early 20th century, people wondered how industrialized production and traditional craftsmanship could be reconciled. In these prefabricated houses, we sought the precision and consistency of industrialized production in the details and the emotional appeal of one-of-a-kind homes. For consistency, the window trimming, baseboards, bridgeboards, and similar elements are factory-made. Fixtures and units such as doorknobs, towel hangers, and prefabricated bathrooms were developed at the same time and can be purchased separately at Ryohin Keikaku ("Muji") stores.

Muji places priority on cost performance when it develops products, and by now, it has put a wide variety of products on the market that relate to our everyday lives. In 2003, the company developed and began selling Muji Infill Wooden Houses as a compilation of all its products. Muji Infill Window Houses are the second round of Muji's housing products. They were developed in 2007 as compact, refined urban dwellings that can be built on small lots in the central areas of cities. This is another showcase for Muji's attempts to provide a total lifestyle based on a uniform design concept.