Japanese cemeteries are somewhat different from the ones in the United States. First, the headstones are extremely close together; secondly, most have a place for leaving offerings. Space is very limited, so most Japanese are cremated. The urns are usually placed in a sealed chamber somewhere near the large monument. The large headstones have the family name engraved and many family members can be inurned at this site. Individuals' names are usually carved on the sided of the topmost stone.
This short video illustrates a typical visit to a family grave.
"In Japanese Buddhism, people traditionally visit their ancestral graves around equinox days. They place flowers, foods and drinks that the deceased used to love, offer incense sticks at the tombstone and tell her/him how they have been doing these days." Source: YouTube