double-grave system
Historical Japanese burial custom where the body is interred in one grave (埋め墓) and a separate grave (詣り墓) is used for memorial services and prayers.
The double-grave system was a custom seen mainly in western Japan.
I learned about the double-grave system in a folklore class.
The grave for visits and memorial services, distinct from the burial grave in the double-grave system.
Compound of 両 (ryō, 'both') + 墓 (bo, 'grave') + 制 (sei, 'system'). The term describes a historical Japanese burial practice.