|Description||list of historical designations and other special listings|
Has Important Cultural PropertiesCastles that have buildings, gates, turrets, main keep, etc that have been designated as an Important Cultural Property. Technically, the designation National Treasure is a subset of Important Cultural Properties. You can see a list of castle related architecture in the Cultural Heritage Online database (sorry, Japanese only).
Has National TreasuresCastles that have buildings, gates, turrets, main keep, etc that have been designated as a National Treasures. Technically, the designation National Treasure is a subset of Important Cultural Property.
Local Historic SiteThese are historical sites that have not been named as National Historic Sites nor Prefectural Historic Sites but have been selected for recognition by local municipalities.
National Historic SiteCastles that have been Nationally designated as historical landmarks by the Ministry of Education. This is an ever changing category as you sometimes see castles newly registered as National Historic Sites. If a site had been previously designated as a Prefectural Historic Site at the prefecture level and is then named so at the National level, then the prefectural designation is removed. Historical landmarks to be considered for national recognition should be important sites to the understanding of Japanese history and hold sufficient interest for academic and research purposes. While it's not officially part of the process, my understanding from people who have been involved with the process is that there is also much burden on the local municipality to prove that historical significance and they need to make some commitment to protecting and preserving a site for it to gain such recognition.
Next 100 Castles
Following on the success of the original Top 100 most famous castles, published in 2006 by the Japan Castle Foundation, the same organization has released a list of the Next 100 Most Famous Castles. I'm a little disappointed that they kept the same criteria insisting that every prefecture be represented and no more than 4 for any one prefecture. Some very good castles have surely been looked over while some unworthy and mostly unknown castles have been included.The castles included on this site are linked below.
Prefectural Historic SiteThese are historic sites that have not been named as National Historic Sites but meet the appropriate prefectural criteria for selection.
Prefectural TreasureA building designated as a cultural treasure by the prefectural government.
Registered Tangible Cultural PropertyThis is actually a fairly broad historical designation applied to buildings and artworks. It may be designated on the national, prefectural, or local administrative levels.
Special Historic SiteNational Historic Sites that have been named by the Ministry of Education as being especially important nationwide to the fields of history or other academia.
Top 100 Castles
In February 2006, the Japan Castle Foundation released a list of the Top 100 castles in Japan. Selection was based on (1) important cultural or historical artifacts (2) the setting for important historical events and (3) representative castles from each historical period and region. Furthermore, there is at least one castle from each prefecture, but no more than 5.The castles included on this site are linked below.
Top 100 Mountaintop CastlesThis is not really an official list but I like the list and ranking so I'm including it here as a category. There are also at least three books using the same list so it is well known. Here is one such book 日本の山城100名城.
UNESCO World Heritage Site
Castle sites that have been recognized by UNESCO as a World Heritage Site. Hikone Castle is also on the recommended list but has not been accepted yet. For more information about the World Heritage Sites in Japan, see this page from UNESCO.