The 12 castles are Hirosaki, Matsumoto, Maruoka, Inuyama, Hikone, Himeji, Matsue, Bicchu Matsuyama, Marugame, Matsuyama, Kochi and Uwahima. These 12 cities with the original donjons are planning to make an alliance called "Existing 12-Castle Donjon Alliance ".
They want to attract more foreign tourists with an eye to the 2020 Tokyo Olympics and Paralympic Games.
I think the concept is good, but that kind of project lead by politicians often wouldn't go well in the end. Using the web efficiently would be the key to success. I believe that inviting many YouTubers and bloggers is a good for boosting popularity of tourists.