Aoyama Kofun is a modest tomb among many, one of the Furuichi mounds in southeastern Osaka that together make up a landscape of burials from the fifth century and thereabouts. The ride calls it by a nearer town, Kashihara, but the ground is the Kawachi plain, below the Kongo and Katsuragi hills, and the character is residential: low houses, small shops, canals of traffic on the main roads and quiet lanes that circle the mounds.
What you find is a forested hump of earth, fenced and signposted, set in the middle of ordinary life. Sometimes you see the keyhole outline only from the map; from the ground it is a tree-covered rise that the street goes around. That is the odd charm of the Furuichi group. The tombs were once strikingly bare, with sloping flanks covered in river stones and lines of clay figures. Today they have grown into small forests, and the birds love them: you hear warblers and bulbuls in spring and see herons in the moats.
The riding here is a patchwork. Fuel is trivial to find, because Habikino and Fujiidera and the larger neighbouring cities are close, and the main roads are lined with the usual Japanese convenience stores where you can get a hot coffee and a rice ball for the price of a small coin.
Japan's earliest rulers were not buried in obscurity. They were buried in an enormous show of power, and the scatter of satellite tombs around the big ones suggests a system: relatives and officials were interred near their lord, a kind of political map written in soil. Having seen the grand tomb of Ojin close by, an afternoon among the smaller mounds like this gives you the full picture of the culture.
Come in the cool months; March and April bring blossom, and November is dry and bright. Avoid the midsummer afternoons, when the plain turns into a sauna and the cicadas sound like machinery.