They share the same dimensions, 5.15 m in length and over 10 tons in weight. Each cannon was marked from number 1 to 9 and carved with its name after the Four Seasons (Spring, Summer, Autumn and Winter) and Five Elements (Metal, Wood, Water, Fire and Earth) respectively. The former group are presently placed near The Nhon gate and the later group are set near Quang Duc gate. The usage instruction of the gunpowder, method of shooting and name of the cannon casters were carved on the cannon body. In 1816, all of them were entitled “The Holy Majestic Unbeatable Senior Lieutenant General” by Gia Long emperor. This title and the date were formed as bas-reliefs at the back belt of these cannons. 

Nine Holy Cannons were originally set at two sides in front of Ngo Mon main gate. In 1917, they were removed to the present place.

In 2012, Nine Holy Cannons were recognized as the National Treasures of Vietnam.

- 360^o view of  Nine Holy Cannons:

https://sketchfab.com/vudn54/collections/than-cong