At the foot of the Shiomi-zaka on the eastern side of the Honmaru lies the Ninomaru (二の丸?, second enceinte) of Edo Castle. A palace for the heirs of the Tokugawa shoguns was constructed in 1639 in the west area and in 1630 it is reported that a garden designed by Kobori Enshu, who was the founder of Japanese landscaping, was located to its south-east. Several fires destroyed whatever stood here and it was not reconstructed. Aside from the Honmaru palace, the Ninomaru was surrounded by 7 keeps, 8 defense houses, approximately 10 gates and other guardhouses. The Tenjin-bori separates a part of the Ninomaru to the Sannomaru.
Several renovations were carried out over the years until the Meiji era. A completely new garden has been laid out since then around the old pond left from the Edo period. Only the Hyakunin-bansho and Dōshin-bansho are still standing.
Read more about this topic: Edo Castle