Without doubt, you get the best impression of this WHS from an aerial view. Shortly after the departure from Kansai Airport westwards you have a perfect view of the Mozu Konfun complex. It is strange to see these huge tombs like green islands in the middle of a sea of ​​modern buildings. One inevitably wonders what this densly populated area may have looked like in the 5th century when the largest of these kofuns were built. And what remains of this ancient culture might still be hidden underground. However, the builders of these tombs have left no written records, no remains of palaces or fortifications have been preserved. Only the kofuns and the artifacts that were found in there.

Visiting this WHS at street level is odd and unsatisfying. What you can see are tree-covered mounds and the moats that surround the larger kofuns. From this perspective, their keyhole shape can only be guessed. The kofun of Emperor Nintoku is the largest of the inscribed tombs. However, there are also doubts as to whether it is really Nintoku’s tomb. Certainly an important person was buried there, the kofun has a total length of about 800 meters and is one of the three largest tombs worldwide. You can walk around on a circular path, but there is not much to see apart from the closed entrance gate and the outermost of the three moats.
I liked the medium-sized kofuns better, where you have an unobstructed view to the actual burial mound: the Gobyoyama kofun or the Itasuke kofun with the ruins of a bridge.
The smaller tombs would receive little attention if they were not included in the WHS. However, all have information boards in English, even the smallest with a diameter of only about 20 metres.

The Sakai City Museum, just across the street from the Nintoku-Tenno-Ryo Kofun, offers a virtual reality drone tour that shows the tombs from a height of 300 metres. Unfortunately, I was too late for the morning tour and the afternoon tour was already fully booked on the day of my visit, so I cannot report on that.
Alternatively, you can go to the observation lobby of the Sakai town hall (21st floor, 80 m high, free entrance). The photo shows the view of the Nintoku-Tenno-Ryo Kofun, so you can assess whether it's worth a visit. In my opinion it is not.

The WHS consists of two clusters with a total of 49 kofuns of different sizes and shapes, only the larger ones are surrounded by moats and have a keyhole shape. I only visited the Mozu Cluster, but I don't think the Furuichi kofuns have other or deeper insights to offer. You can reach the Mozu kofuns by train on the JR Hanwa Line (Mozu Station) in about one hour from either Kansai Airport or Shin-Osaka.