⑤ Honmaru

This inner-most complex of Honmaru site, currently covered with an expanse of green lawn, was mostly occupied by Honmaru Goten with many Sumi-yagura (corner towers) and Tamon-yagura (hall turret) surrounded. Unfortunately, Honmaru Goten was burned down in the Fire in 1683, and was never reconstructed.

In the old photograph taken in 1871 shows the devastated state of Honmaru site.

Honmaru Goten had three main parts of buildings, from the south to the north, Omote, Oku (also called Nakaoku) and Ooku. Behind them was a main Tenshu (donjon). This area measures about 114,000 square meters. There was no specific boundary between Omote and Oku, but Nakaoku and Ooku were strictly separated, only connected by Osuzuroka Corridor.

The Omote (great outer palace) in the south side of the Honden, used for the politics and state of affairs, consisted of Ohiroma, Shiroshoin and Kuroshoin.

They were used for ceremonious rooms and reception rooms.

Ohiroma was counted as the largest and most ceremonious room in Edo Castle. The utmost solemn ceremonies such as the appointment of Seii Taishogun were observed here. Ohiroma had 4 level tiered floors with tatamimat, Jodan (the upper level floor), Chudan (the middle level floor), Gedan (the lowest level floor) and Irigawa (corridor space). It was strictly specified who sat where in Ohiroma, in accordance with attendee's political and social status. The Matsunoroka Corridor, famous for the Forty-seven Ronin incident (Chushingura) in 1701, combined Ohiroma and Shiroshoin, and it is said to have been the second longest corridor in Edo Castle with a total length of 60 meters.

The Nakaoku (middle interior) was the shogun's official residence, consisting of Gozanoma (shogun's office), Gokyusokunoma (rooms for state of affairs as well as shogun's spending daily life), and his private residence including kitchens and bathrooms.

Ooku (great interior) contained the private residences for the shogun, his wife, female servants, and so on.

According to the records written in the days under the fourteenth shogun Iemochi, a total of about 400 female servants lived here during the peak period. Comic books and movies set in Edo have often depicted historical female figures such as Princess GO, Kasugano Tsubone and Princess Atsu who resided in Ooku in the days of glory, to entertain today's Japanese audience.

⑥ Tenshudai(donjon base)

Tenshu (donjon) of Edo Castle was considered a symbol of the reigning shogun's power, so that it was reconstructed at each time of assumption of office.

Tenshu which was originally constructed by Ieyasu in 1606, was reconstructed by Hidetada in 1622 and by Iemitsu in 1638.

The first Tenshu built by Ieyasu, was the coalition formula castle tower to extend the southeast corner around Daitenshu (great tower), with the structure called Tenshu Kuruwa (tower citadel) including Niju-yagura and Sukiya-tamon.

It is estimated that the first Tenshu was located in the current Fujimi-tamon-yagura area. The Tenshu of the Kan'ei era was a five-story building of painted with black lacquer over 60 meters of the height, but was burned down by the Great Fire of Meireki in 1657.

The following year, MAEDA Family of Kaga Domain built Tenshudai (donjon base) with stone walls of 18 meters made of granite.

The rebuilding of the Tenshu was postponed, however, as priority was given to the reconstruction of the castle town, and was finally given up by the suggestion from HOSHINA Masayuki, an influential retainer of the shogun.

There was Kitahanebashi Bridge with Kitahanebashi-mon Gate, to the north of Tenshudai. Kitahanebashi Bridge was a buscule bridge for the defense of Honmaru. Two diagonal gutters against the Kitahane-iwakita-mon Gate on the photograph were for watersupply.

⑦ Stone Walls around Hakuchobori Moat and Shiomizaka Slope

There was over 10 meters difference in level of Honmaru and Ninomaru and digged moats along the steps to protect Honmaru, with Bairinzaka Gate and Shiomizaka Gate built as well.

It is said that the sea could be seen well from this slope before Hibiya Inlet was reclaimed in the Edo period, so it was named Shiomizaka Slope.

Honmaru was originally encircled by the moats, but Hakuchobori Moat is the only moat which remains in the eastern side of Honmaru, and among the sites opened to the public, this area is also the only place where we see the stone walls constructed in the era of TOKUGAWA Ieyasu. This stone wall was built by the traditional methods, Ranzumi (masonry work with stones different in the size) and Uchikomihagi (implant grafting) method, and made each corner having a slight curve by using the traditional form of construction called Sangi-zumi (trimmed style piling) method.

As the stone walls located between Shiomizaka Slope and Bairinzaka Slope were built to enlarge Honmaru after the Great Fire of Meireki, it can be said that they are rather young as compared with other stone walls around the Honmaru area. This site of stone walls was built by Kirikomi-hagi method, piling stones very tightly without any gap between them, and Nunozumi method, piling square stones regularly. It will be enjoyable to compare the various methods of piling stones rather easily here!

∗ All of old photograghs are possessed by Tokyo National Museum.
∗ These photographs in the East Gardens of the Imperial Palace were taken with permission of the Imperial Household Ageney.