At one point, the two monsters exchange blows across a castle, destroying it. Anyone know the name of that castle?
shareIt was the emperor of Japans house
shareNo, it was the tall central keep of a castle built by a feudal lord.
The imperial palace in Kyoto was a wide complex of comparatively low buildings and courtyards.
Japanese castles had several concentric walls and courtyards and tall central keeps.
The Shogun, who ruled Japan while the Emperor reigned, had his headquarters in the greatest castle in all Japan, in Edo. During the Meji restoration in 1868, the last Shogon was deposed and the Emperor became the ruler of Japan. the imperial court moved from the palace at Kyoto to the castle of the Shoguns in Edo, which was renamed Tokyo.
The tall keep of the Shogun's castle was destroyed in a fire in 1657 and so the imperial palace didn't have a tall central keep when KIng Kong vs Godzilla was made.
Another answer says it is Atami Castle, which is a modern castle built in 1959 as a tourist attraction. And Godzilla websites agree.
https://godzilla.fandom.com/wiki/Atami_Castle