According, the excavation will be expanded to the defending canal area in the northern part of the citadel in Vinh Tien and Vinh Long communes, Vinh Loc district, Thanh Hoa province.

The expanded area is around 1,000 sq.m, bringing the total excavation area in the northern defending canal area to 3,000 sq.m.

The expansion aims to determine the scale and structure of the northern canal for the research and preservation of the ancient water system and to improve the landscape serving tourism development at this world heritage site.

The Ho dynasty citadel, a unique stone architectural work in Vietnam, was built by Ho Quy Ly in 1397. It was also known as Tay Do to distinguish it from Dong Do (Thang Long - Hanoi). After the citadel was completed, Ho Quy Ly moved the capital from Thang Long to Tay Do. Most of the buildings inside the Citadel were destroyed, and for most of the over 600 years since it was built, the traces of the foundations of the old palaces lay hidden under the rice fields.

The citadel was recognised as a world cultural heritage by UNESCO in 2011./.