Otepää castle hill is the site of an ancient stronghold. It is speculated that a fortified settlement may have existed there even before Christ. The first major extension works were initiated in the 11th and 12th century when the castle was at the crossroads of important trading routes. Herman I, the bishop of Tartu, established there the first stronghold of its diocese. A settlement, which was mainly populated by craftsmen and merchants, appeared around the bishop’s castle in the 13th century. The castle was the first known brick building in Estonia.
References: VisitEstonia, turismiweb.ee
Goryōkaku (五稜郭) (literally, 'five-point fort') is a star fort in the Japanese city of Hakodate on the island of Hokkaido. The fortress was completed in 1866. It was the main fortress of the short-lived Republic of Ezo.
Goryōkaku was designed in 1855 by Takeda Ayasaburō and Jules Brunet. Their plans was based on the work of the French architect Vauban. The fortress was completed in 1866, two years before the collapse of the Tokugawa Shogunate. It is shaped like a five-pointed star. This allowed for greater numbers of gun emplacements on its walls than a traditional Japanese fortress, and reduced the number of blind spots where a cannon could not fire.
The fort was built by the Tokugawa shogunate to protect the Tsugaru Strait against a possible invasion by the Meiji government.
Goryōkaku is famous as the site of the last battle of the Boshin War.