Hello /askHistorians, I visited Nijō castle in Kyoto today and as a european used to castles of the middle age, a few things seemed very odd to me, which also apply to other Japanese castles.
The incredible thickness of the walls: The walls in Nijō castle are way thicker than the ones from european castles of the same age: was this an actual necessity (e.g. did the Japanese have stronger siege weapons) or to show of wealth and power? Also the rather average height seems to make an odd combination.
The lack of battlements: The walls all around Nijō castle have no battlements, guards just seemingly stood on top of them unprotected from accidentally falling or enemy archers. Did the Japanese not have the need for battlements on top of their walls (i remember reading somewhere that archery was considered cowardly so maybe they weren't used in battle)?
The gate on Nijō castle's west side: This one applies only to this particular castle. When leaving the grounds we noticed a gate on the west side of the walls leading nowhere with no signs of a bridge: what was it's use?
For better understanding my questions I commented an imgur album with a few explanatory pictures: I don't know if the mods allow that but for the sake of answering my questions please bare with me mods :)
These may be hard to answer, but I'm thankful for any answer or theories you come up with. :)
The walls you see are just the rock base. Rock bases are thick not to protect against any siege weapons but to protect against nature. Regular earthquakes and typhoons are not kind to large architecture. These require solid base to prevent collapse. Previous techniques of cutting into hills or using packed earth simply wouldn't cut it for a gigantic, long-term castle, so rammed-earth rock-face walls were developed. You can see this in Kumamoto Castle's walls damaged by the recent earthquake. Although Nijō, being constructed after the Korean Invasions, could have been designed to withstand gunpowder artillery. Then again, the artillery bombardment of Osaka Castle seem to have targetted the wooden superstructure, as catapults did before. And Hiroshima castle was constructed before the Korean Invasions and its rock base mostly survived the atomic bomb going off 1km away. Not totally, but still pretty impressive.
When Nijō was first constructed, on top of all the rock base would have been wooden walls with gun/arrow slits, painted white, and the actual towers (four in the corners, the two southern ones are still there) like a proper Japanese castle. There was also a central keep, again, like a proper Japanese castle (when I was there last year I remember a plaque explaining that at the rock base of the keep, but I don't remember if it had an English translation). The keep was located on the south west corner in the inner bailey and the other three corners also had towers. The keep (and maybe other buildings) burned down in 1750. Some towers (the two northern ones?) and some buildings burnt down in 1788. The Mid-Late Tokugawa Shogunate seemed to have a policy of not rebuilding destroyed castle architecture, probably because it was very costly but served no purpose as there's no war to fight.
When Nijō was in operation there was a bridge out of the west gate.
The album of the castle
The Wikipedia article about it
