With the recent rise in perpetual memorial services and the closing of graves, I looked into how Buddhism views the closure of ancestral graves. What happens if the remains are not treated with care? Will treating them carelessly bring about retribution?

The bottom line is that how the remains are treated is completely irrelevant. Whether memorial services are held or sutras are recited... these things have absolutely no bearing on the original teachings of Buddhism. It's fine to close the grave, not to bury the ashes, or even to scatter them. Apparently, how the remains are treated doesn't improve or worsen the lives of the surviving family members who have seen off the deceased. This doesn't mean it's okay to treat the remains carelessly, but rather, what surviving family members truly need to respect the feelings of the deceased. I learned that the most important memorial service for the deceased is not to treat the remains carelessly, but to respect the feelings of the deceased. I was taught that the deceased's greatest wish is for their surviving family members to walk the right path and live a life of dignity.

Reference: "Learning Happiness from Buddhism by Ryuta Kikutani"
https://www.youtube.com/watch?v=Lx_1tb-LyNM

"Forest scattering" is a natural burial where the remains are returned to nature. It is similar to "tree burial," which involves burial at the base of a tree, but is slightly different. While "tree burial" involves digging a hole in the ground and burying the remains in an urn, "forest scattering" involves grinding the remains into a fine powder beforehand and scattering them in the mountains. The remains are not buried underground, but rather scattered over the ground like the "Grandpa Who Made Flowers Bloom." In the wild, grass grows and bare ground is rarely found, so the white remains are not left in one place. The powdered remains gradually return to the soil as they are exposed to wind and rain. Furthermore, while in a typical "tree burial," the remains are exhumed and interred after a certain number of years, in the case of "forest scattering," the remains cannot be manually retrieved, so they rest there forever. Japan has a long tradition of "mountain worship," which views the entire mountain as a sacred object. ・・・

"Ocean scattering" is a funeral method that has become popular not only in Japan but around the world. Scattering ashes into rivers is not permitted in Japan, so this method seems to be gaining popularity. It is particularly popular as a way to say goodbye to a deceased loved one, and services such as chartering a motorboat or cruiser to scatter ashes offshore are popular. However, the drawbacks of this method include the fact that the ocean is easily affected by weather, which can suddenly result in a cancellation on the scheduled date, and the relatively high cost of chartering a boat. Our company, SANKOTSUYAMA, offers an "Ocean Scattering Plan," which uses our small boat, eliminating the additional cost of chartering a boat. All costs are included in the price. Furthermore, "ocean scattering" does not necessarily require the services of a specialized scattering company. Individuals are not prohibited from scattering powdered ashes into the sea. However, scattering ashes is prohibited near fishing ・・・