Ii Naomasa, awarded Hikone for his Sekigahara service, planned the castle but died before construction began. His sons Naotsugu and Naotaka completed it in 1622. Construction materials were transferred from neighboring Sawayama and Otsu castles; the keep itself is said to be the relocated Otsu Castle keep. As the leading fudai daimyo, the Ii held the castle through fourteen generations until the end of the Edo period. After the Meiji Castle Abolition Order, Ii Naonori bought it back privately for preservation. The keep was designated a National Treasure in 1952.
A three-tier, three-story keep on top of Konkiyama hill, wrapped by three concentric moats (inner, middle, outer). The keep is small by national-treasure standards (about 21m) but combines hip-and-gable, plover, and Chinese-style gables in a meticulous study of function meeting form. The castle town is planned around the connection to the Nakasendo highway, with merchant, samurai, and temple quarters set orthogonal to the road.
Hikone's design philosophy: not the largest castle, but the most important location. The Ii were placed at the geopolitical chokepoint between Edo (the east) and Kyoto (the imperial west) — so the castle didn't need to be a flashy military stronghold. It was optimized as a quiet checkpoint monitoring information, logistics, and traffic.
Hikone is the clearest lesson in "location as strategy." The Ii didn't build the largest castle — they built where it mattered most. In any era, controlling the chokepoint beats controlling the largest area. The logic shows up again at SaaS API integration points, logistics hub ports, and station-front urban development.
From the front-gate bridge up to the keep takes 12 minutes. The summit is smaller than expected, but the main bailey gives a panoramic view of both Lake Biwa and the Nakasendo highway. Genkyu-en, a pond garden using the castle as borrowed scenery, complements the ground-up view — design intent becomes three-dimensional when walked together. The Yume-Kyobashi Castle Road below is reconstructed merchant streetfront but has strong foot traffic.