An increasing number of graves have been abandoned across the nation as no one is taking care of them due to lower birthrates and depopulation.
A range of serious problems have arisen, including unkempt graveyards and overdue payments for managing the graves.
There are about 30,000 public cemeteries around the nation, and some local governments have started removing neglected graves and transferring remains to charnel houses and other places using public funds.
At the Tokyo metropolitan Yabashira Reien cemetery in Matsudo, Chiba Prefecture, a signboard on one tombstone reads, "If you are related to the deceased, please inform us within one year."
The grave is now being surveyed in preparation for transfer because the annual administration fee of about ¥2,500 (S$28) has been unpaid for many years.
If a relative fails to come forward, the tombstone will be removed and the remains transferred to the cemetery's special tombs, which hold unclaimed remains.
To transfer remains in graves to other graves or charnel houses, approval is required from heads of wards, cities, towns and villages.
About 1.28 million remains are interred in eight cemeteries operated by the Tokyo metropolitan government.
In fiscal 2000, the Tokyo government started surveying neglected graves for which administrative fees had not been paid for more than five years.
Of about 2,800 graves surveyed between fiscal 2009 and fiscal 2013, 1,095 had no surviving relatives.
The remains are transferred to other places and the grave sites are lent to others who want to use them.
Including tombstone removal, redeveloping a site for one grave costs ¥300,000 to ¥400,000.
Due to an increasing number of neglected graves requiring removal and transfer, existing special tombs used to store such remains are unable to accommodate all of them.
The Tokyo government prepared a new site to accommodate about 6,000 urns for remains interred at abandoned graves at the cost of about ¥40 million in fiscal 2012.
An official at the Tokyo government's Park Division of the Bureau of Construction said: "It takes money and effort to remove and transfer neglected graves.
"To prevent graves from being abandoned, we suggest group interment sites for those without relatives to attend their graves while they are alive."
Changing family structures
In urban areas, there are an increasing number of cases in which graves are neglected because of changing family structures, mainly stemming from lower birthrates and rising numbers of unmarried individuals as well as rising divorce rates.
In a survey by the Kawasaki city government in 2012, 53 per cent of respondents were worried they would have no surviving relatives at some point in the future.
The city confirmed around 30 neglected graves at its municipal cemeteries, and plans to remove and transfer them in the near future.
The problem is becoming a serious one in rural areas suffering from depopulation and an outflow of young people.
In Kumamoto Prefecture, half of 14 local governments that have municipal cemeteries complained in 2013 about an increasing number of neglected graves, with many at risk of collapsing.
Following a survey of 15,123 graves, including those at private cemeteries, by the Hitoyoshi city government, more than 40 per cent were found to be neglected.
Rising death toll
The nation's annual death toll topped 1 million in 2003, and is estimated to reach a peak of 1.67 million in 2039.
Demand for graves may be rising, but so are expectations that more and more graves will become abandoned.
In Tajimi, Gifu Prefecture, and Sagamihara, Kanagawa Prefecture, a range of measures are being taken to stem the trend including the establishment of a panel of representatives from various fields to discuss the future of public cemeteries.
The local governments are considering selling sites occupied by neglected graves to applicants after redevelopment, and preparing common graves for those without relatives to tend to their graves.
Prof. Yoko Nagae at Seitoku University, who studies the culture behind graves and funerals, explained: "Many are unaware that neglected graves are removed and transferred.
"Local governments handling abandoned graves are required to give careful consideration to these graves, for example by carrying out sufficient surveys to maintain records for any relatives that might come forward."