I’ve been visiting Samurai castles in Japan.
A fair number survive, in some form or other, but authenticity varies wildly. Some keeps, such as Osaka-jo, are imaginative rebuilds, with concrete cores and even elevators. But there are a handful of authentic survivors and I focused on the five that are ranked as “National Treasures”, at Matsumoto, Hikone, Himeji, Inuyama and Matsue. Even these have seen extensive renovations.
These mostly follow fairly similar patterns, with complex moat systems and walls protecting the route to the inner keep. Inuyama-jo is a striking exception, using a natural hill and river instead of moats.
There are many repeated design tricks, such as double gates at right angles, with a weak outer gate allowing entry to a small courtyard and then a very strong inner gate making sure you stayed there, as convenient target practice for the defenders.
