KOBE, Japan -- Panoramic views and walking-distance commutes are just some of the advantages that have made high-rise condominiums in city centers popular among the Japanese. But Kobe sees them as potentially disruptive to city planning and will introduce a sweeping ban on such construction projects in July 2020.

Kobe is determined to prevent "tower mansions," as they are known in Japan, from absorbing the residents of the city's more suburban areas and leaving them abandoned as ghost towns.

"The nightmare scenario is that some years into the future, the city center will suddenly be filled with old people, while suburban areas are depopulated and ruined," Mayor Kizo Hisamoto said recently.

As the population declines nationwide, maintaining sustainable development in both urban and suburban areas will be a challenge for many cities.

Kobe's ban will prohibit the construction of tower mansions within a 22.6-hectare circle from the central rail station of Sannomiya. In a wider 292-hectare circle that includes the Shin-Kobe shinkansen bullet train station, the ratio of building volume to land lot will shrink to 400% from the current 900%, in effect making it impossible to build a high-rise.

Though a high-rise contributes to population growth in the city center, Kobe officials fear that tower mansions will render the city a mere bedroom town for people who work in the nearby megacity of Osaka, depriving Kobe of commercial and office buildings of its own.

People also are likely to flow in from suburban communities within the city that were formed over the years as housing developments, leaving them empty.

Kobe's population peaked in 2011, and government statistics show the number of Japanese citizens residing in the city fell by 6,235 in 2018, the steepest drop among all municipalities in the country.

Though Kobe is a major regional city of western Japan, it lacks the gravity to pull in heavy inflows as Tokyo or Osaka can do.

Instead of high-rises, Kobe is encouraging new generations to move into housing developments outside the city center. Kobe has readied "moving in" subsidies for families raising children, and is remodeling empty houses into shops and offices to encourage younger people to move there.

But real estate developers are turning a skeptical eye to the policies.

"Even if you shut out tower mansions, there is no guarantee that people will move to the suburbs," one developer said. "If they move to another city and the tax revenue goes down, that would be more of a problem for city development."

Sapporo, the largest city on the northern island of Hokkaido, has enacted a similar policy. When Sapporo relaxed the ratio of building volume to land lot in the city center to spur development of offices and hotels, the deregulation did not apply to condos.

"We did not think it appropriate to have condominiums around the iconic Odori Park area," a city official explained.

The increase in condos has forced the annual summer beer garden festival, an Odori Park favorite with a 60-year tradition, to change its operating hours. Residents of the dozen or so tower mansions that were built in recent years have complained about the noise from the festival.

Professor Chie Nozawa of Toyo University says it is understandable that local governments have begun placing restrictions on tower mansions.

"An oversupply of housing in a declining population will inevitably lead to an increase in empty houses," she said. "Action must be taken to protect the asset value of the entire city."