Glossary
Kenpei-ritsu (building-coverage ratio)
The legal cap on a building's footprint relative to lot size, controlling how much of a plot the structure can cover.
Kenpei-ritsu is the building-coverage ratio: the building's ground footprint divided by the lot area, as a percentage. A 60 percent ratio on a 100-square-meter lot means the building can cover at most 60 square meters of ground, leaving the rest as open space. It works alongside the floor-area ratio — coverage governs how much of the plot you fill, floor-area ratio governs total floors of space — and together they cap what's buildable. Corner lots and fire-resistant construction can earn small bonuses to the coverage limit. For buyers this matters most on land or redevelopment plays, where a tight coverage ratio quietly shrinks what you can put on the site.