"Ninomaru" garden and what is presently known as "Ninomaru" East Garden were once part of the "Ninomaru" palace grounds and was built between 1615 and 1623 under Tokugawa Yoshinao, when the "Ninomaru" palace was constructed. The sanctuary on the north side of the palace was its centrepiece. It was transformed into a Japanese dry landscape garden in 1716. Although its area garden is small, it was designed to represent steep hills, forests, and deep valleys. Many large rocks are within its boundaries. On top of the hill the thickly growing trees offered the lord protection from enemies by providing a hiding place and a secret escape route. These characteristics of the garden have faded over the years, but the basic structure still remains. The garden has been expanded and undergone restorations over the years, especially between 1818 and 1829/1830 under the tenure of Tokugawa Naritomo, when the Ninomaru East Garden was completed.The Ninomaru garden was designated a National Place of Scenic Beauty in 1953, with the area under protection expanded in 2018 to encompass most of the Ninomaru East Garden as well.