Living in a one-room house with an ultra-minimalist aesthetic and two small children sounds more like the setup for a joke than something any reasonably sane person would attempt.

And yet that’s exactly what Takaaki and Christina Kawabata set out to do when they renovated an old house here. They were convinced that an open space with as few toys and material possessions as possible was a recipe not for disaster, but for domestic calm.

Still, living this way takes a kind of discipline that many find hard to fathom.

“Most of the people we’ve invited here are shocked by how we live,” Ms. Kawabata, 41, said. “How we can raise kids without toys and clutter and stuff everywhere.”