From a mountaintop of Mt. Dakesan, also called Mt. Oshima-Fuji, you can overlook almost the whole eastern part of Oshima and beautiful islands peculier to Seto Inland Sea.
The driveway has been prepared all the way to the mountaintop, and besides the observatory there's a launcher stand for hang gliding and paragliding, so you can enjoy sky sports as well.
Besides, from autumn to spring, the hiking trail on the mountainside is crowded with many hikers.
In addition, the Halfway up a mountain has the Hiking Course with an ocean view, too and I hang it in spring from autumn and am full of a large number of hikers.