Its leaky roof rested on ten-foot-high walls that were originally constructed as a sandwich: vertical rock faces of rounded fieldstone on the outside with a mud-mortar/rubble stone mix on the inside.

KYOTO--A stone wall unearthed at the ruins of Fushimi Castle here suggests that 16th-century warlord Toyotomi Hideyoshi built the structure with the latest quake-resistant techniques after a ...