The hilltop ruins of a once-formidable castle on the forested ridge north of Hikone city centre. Sawayama was a significant fortification in the late Sengoku period, associated with Ishida Mitsunari, one of the key figures of the Battle of Sekigahara. After Mitsunari's defeat in 1600, the castle was dismantled and its materials reused for Hikone Castle; only earthworks, ditches, and the faint outline of stone foundations remain.
The climb to the ruins takes about thirty minutes through cedar forest and rewards with good views of Lake Biwa. The site is often empty — a welcome contrast to the busy castle below. Wear decent shoes and bring water.