The situation today would have been unimaginable back in Japan's postwar rapid growth period, when a steep population increase and development boom generated robust demand for land across the country. An increase in the number of land plots whose ownership is unknown, along with a sharp rise in vacant housing, appears to symbolize the state of Japanese society today with its rapidly graying and shrinking population. The government plans to take steps to remove obstacles to the use of such private land for public works projects. But there should be broad-based discussions involving various sectors to reach fundamental solutions that are capable of resolving the problem of unclaimed land plots, and can facilitate the use of such properties.

The ownership of land plots becomes unknown when the original holders die and nobody inherits them, or when heirs do not transfer the ownership either due to the cumbersome procedure or to evade fixed-asset taxation or the financial burden of managing the land. The registration process is not mandatory and entails a fee, and is often shunned when plots are deemed to be of little value or when the new owners have no immediate plans to sell them.

Such properties have expanded across the country as the value of land in many rural areas dropped with depopulation and the exodus to urban areas. In a sample survey by the land ministry in 2016, land plots whose owners could not be confirmed in real estate registries account for some 20 percent of the total. A private think tank estimates that the total area of such properties is already greater than the size of Kyushu — and warns that their combined area could grow to 7.2 million hectares — or an equivalent of 90 percent of Hokkaido — by 2040 if no action is taken. It's feared that the problem will get worse in coming years when members of the postwar baby boomer generation pass on their land assets to their children.