Large fortified edifices called dzong (རྫོང་) are common landmarks across Bhutan. Found at strategic locations such as ridges or river confluences, dzong are centres of religious and political life. Ever since the unification of Bhutan in the middle of the 17^th century, dzong have been the main seats of political power. Even today, most of them are the headquarters of the national and/or district administration. They are also the main base of the state monastic communities.

The word dzong (རྫོང་), in its original sense, referred to a site that was difficult to access or reach. Some remote and inaccessible natural sites, such as Senge Dzong and Monkha Śrī Dzong in northeastern Bhutan, are still known as dzong. However, with the establishment of towering and fortified structures, the term has come to refer mainly to large built structures today. The built structure of dzong in Bhutan can be roughly divided into three types corresponding to three political phases of Bhutan’s history. The three types have distinct features which are influenced by the resources available at their particular time and their use. One can also see a progressive evolution from the earlier types both in terms of size, quality and function.

The earliest sites known as dzong in Bhutan are some religious establishments founded by lamas before Zhapdrung Ngakwang Namgyel (1594-1651) unified Bhutan. Examples of this group of dzong are Somthrang Samdrup Chödzong built by Nyö Demchog in early 1200s, Jathal Dzong and Dongön Dzong built by the Lhapa tradition in 12^th century, Lingshi Jagödzong and Tango Chöyingdzong claimed to have been built by Phajo Drukgom Zhikpo in the 13^th century, Dobji Dzong and Lhadzong founded by Ngakwang Chögyel in the 16^th century. These were large structures in comparison to the houses occupied by ordinary people. They were also mostly built on spots considered to have some spiritual significance and were primarily religious centres. While some of them became homes of the hereditary lamas, others were run by successive abbots and incarnations. The structures generally looked like a temple and, except for the name, they did not have architectural features which distinguished them from other religious structures such as temples and monasteries. Thus, this type of dzong is considered as dzong primarily because they are called dzong but most people today see them as usual temples.

The most common dzong structures in Bhutan belong to the second type, those built by Zhapdrung Ngakwang Namgyel and his followers in the 17^th century or those which follow this architectural style and function. This type includes the dzong of Semtokha, Punakha, Wangdiphodrang, Thimphu, Paro, Drukgyal, Gasa, Trongsa, Dagana, Jakar and Tashigang. Some dzong built before Zhapdrung such as Shongar Dzong, Hungrel Dzong and Draphai Dzong also have similar architectural style and function. In terms of architectural style and function, these dzong bear some resemblance also to dzong in Tibet which were built earlier or around the same time. They were mainly fortified political centres which housed public administration. As most of the dzongs in the time of Zhapdrung and his immediate followers were built in times of war, they are heavily fortified. The walls of the dzongs are thus very high and often have loopholes from where soldiers could shoot at the enemies. They were also built in militarily strategic spots and access to them is heavily guarded and restricted. These dzong often have a tadzong (ལྟ་རྫོང་) or watch tower on a higher ground, a chudzong (ཆུ་རྫོང་) or water tower at the water source, which is connected to the dzong by a fortified passage. The trade routes sometimes were enclosed within the dzong making it easy to control tolls and taxes on merchants and travellers. The dzong also contained large storage space in the basement to hold grains, dairy products and animal products which were collected as taxes.

Because the church and the state were united and the government was run by monks, the dzong of this type are also mostly monastic centres with large prayer halls and monastic quarters. They contain the kunré (ཀུན་ར་) and dukhang (འདུ་ཁང་) halls for open and esoteric ceremonies and many other temples. These dzongs have a central tower called the utsé (དབུ་རྩེ་), a large courtyard or dochel (རྡོ་ཅལ་) and the surrounding monastic residence and offices called shakkor (ཤག་སྐོར་). As the main residents were monks, women were required to leave the dzong before sunset and this is still the case with most of these dzongs. Today, these dzong house most of the district headquarters and government offices. The state monks of the districts also live in these dzong and the State Monk Body resides in the dzongs of Punakha and Thimphu during the winter and summer respectively.

The third and last category of dzongs belong to the 19^th and 20^th century, which roughly corresponds to the monarchial period. Most of these dzongs were built by monarchs in the 20^th century, mainly as royal residences. These dzongs include Wangdicholing, Lamai Gönpo and Yungdrung Chöling built during the reign of the first King, Kuenga Rabten, Tashi Chöling and Samdrup Chöling built by the second King, Haa Wangchuck Lo and Tashichödzong by the Third King. This third generation of dzong drew largely on the local architectural tradition in their heavy use of timber and overall aesthetics. As they were built by secular rulers during peace times and also were initiated by local Bhutanese, these dzongs have little or no fortification and a much greater use of local timber designs than the dzongs of Zhapdrung’s era. While the dzongs of Zhapdrung’s era have high slanting walls and small wood structures, the walls of the third generation of dzongs are vertically straight with generous use of timber for windows and cornices. Unlike previous generations of dzongs, they are not portrayed as temples or religious centres though a temple or religious space is integrated within them. As they were mainly built as royal residences, they do not follow the restriction on women after sunset. Instead, these dzongs has provisions for courtiers, playgrounds and stables for horses. The dzongs of the first and second generations are prevalent in western Bhutan, which was the medieval power centre, whereas the third generation dzongs are located mostly in Bumthang and Tongsa from where the first two Kings ruled the country.

Today, the dzong edifices of Bhutan are viewed as an outstanding cultural heritage and many of them are centres of attraction for visitors. Most dzongs are in good state and flourishing, and there are many initiatives to expand small ones, renovate old ones and build ones.

Karma Phuntsho is a social thinker and worker, the President of the Loden Foundation and the author of many books and articles including The History of Bhutan.