Ōoku

Edo Castle Gates (江戸城三十六見附) are the gates of Edo Castle in Tokyo. They were placed at crossing points (bridges) of castle moats. Originally, there were 36gates in all. Some remain, others completely demolished. Today, the central quarter of the castle is Tokyo Imperial Palace. So, some gates on the inner moats are still used as security check points. However, most on the outer moats don't exist. Some district in Tokyo are named after the castle gates.Gate is "Mon" (門) in Japanese. Bridge is "Hashi" or "Bashi" (橋).

Edo Castle (江戸城, Edo-jō), also known as Chiyoda Castle (千代田城, Chiyoda-jō), is a flatland castle that was built in 1457 by Ōta Dōkan. It is today part of the Tokyo Imperial Palace and is in Chiyoda, Tokyo (then known as Edo), Toshima District, Musashi Province. Tokugawa Ieyasu established the Tokugawa shogunate there. It was the residence of the shōgun and location of the shogunate, and also functioned as the military capital during the Edo period of Japanese history. After the resignation of the shōgun and the Meiji Restoration, it became the Tokyo Imperial Palace. Some moats, walls and ramparts of the castle survive to this day. However, the grounds were more extensive during the Edo period, with Tokyo Station and the Marunouchi section of the city lying within the outermost moat. It also encompassed Kitanomaru Park, the Nippon Budokan Hall and other landmarks of the surrounding area.

The Independent Administrative Institution National Archives of Japan (独立行政法人国立公文書館, Dokuritsu Gyosei Hojin Kokuritsu Kōbunshokan) preserve Japanese government documents and historical records and make them available to the public. Although Japan's reverence for its unique history and art is well documented and illustrated by collections of art and documents, there is almost no archivist tradition. Before the creation of the National Archives, there was a scarcity of available public documents which preserve "grey-area" records, such as internal sources to show a process which informs the formation of a specific policy or the proceedings of various committee meetings.In accordance with the National Archives Law No.79 (1999), the core function of preserving "government documents and records of importance as historical materials" includes all material relating to (1) decision-making on important items of national policies, and (2) processes of deliberation, discussion, or consultation prior to reaching any decision-making, and the process of enforcing policies based on decisions made. The transfer of what are deemed historically important materials from the various ministries and agencies is carried out on a regular basis in accordance with the Transfer Plan prepared and revised by the Prime Minister for each fiscal year. Preservation, restoration cataloging, microfilming and digitization are all important aspects of the archive's responsibilities. However, the National Archives is in the process of becoming something more than simply a historical repository, because it is also a complex of structures, processes, and epistemologies which are situated at a critical point of the intersection between scholarship, cultural practices, politics, and technologies.

The Tokyo National Museum of Modern Art (東京国立近代美術館, Tōkyō Kokuritsu Kindai Bijutsukan) in Tokyo, Japan, is the foremost museum collecting and exhibiting modern Japanese art.This Tokyo museum is also known by the English acronym MOMAT (National Museum of Modern Art, Tokyo). The museum is known for its collection of 20th-century art and includes Western-style and Nihonga artists.

The Imperial Palace East Gardens is a historical garden in The Imperial Palace in Tokyo. The gardens however, were first in use by the Tokugawa shogunate. There is a bridge which leads to Sakashita-mon gate nearby is the Imperial Household Agency building and Tokyo Imperial Palace (or "kyuden") The garden was built on the grounds of Edo Castle. The Ote-mon Gate functioned as the main gate of Edo Castle. It was used by the feudal lords who came to stay in the castle under the alternating attendance system of the Tokugawa shogunate, as such it was a very important gate. All the gardens areas were used as defence. They are translated as “inner circle of defense” (honmaru), “second circle of defense” (ninomaru), and “third circle of defense” (sannomaru). Suwa-no-cha-ya, was built by Emperor Meiji in 1912 and is a tea house. Emperor Meiji also lived in the Nishinomaru palace near the gardens, he lived at the Nishinomaru from 1869-73.

The Matsu no Ōrōka (松之大廊下, Great Pine Corridor or Hallway) was part of Edo Castle. The name derives from the painted shōji (sliding doors) that were decorated with motifs of Japanese pine trees (matsu). It was the passage which led to the Shiroshoin (白書院) from the Ōhiroma of the Honnmaru Goten (本丸御殿). The corridor measured around 50 meters in length and 4 meters in width. The corridor was the second longest with tatami mats in the castle. On March 14, 1701, Asano Takumi no Kami Naganori attacked and injured Kira Kozuke no Suke Yoshihisa after an insult there, which later led to the bloody incident of the Forty-seven rōnin. The corridor does not exist anymore just like the rest of the Shōgun's palace shortly before or during the Meiji Restoration in the later half of the 19th century. A stone marker with an inscription stands today in its place. The Great Pine Corridor has entered legends in stories such as the Chūshingura and also features in movies, parodies and TV advertisements.

Takebashi Station (竹橋駅, Takebashi-eki) is a station on the Tokyo Metro Tozai Line in Chiyoda, Tokyo, Japan. Its station designation is T-08. It is located directly underneath the headquarters of the Mainichi Shimbun in the Palaceside Building and is directly adjacent to the northern edge of the Imperial Palace grounds. The station is also convenient to such attractions as the National Museum of Modern Art, Tokyo (3 minute walk), and the Japan Science Foundation's Science Museum (7 minute walk).

The Imperial Household Agency (宮内庁, Kunai-chō) (IHA) is an agency of the government of Japan in charge of state matters concerning the Imperial Family, and also the keeping of the Privy Seal and State Seal of Japan. From around the 8th century AD, up until the Second World War, it was known as the Imperial Household Ministry (宮内省, Kunai-shō). The Agency is unique among conventional government agencies and ministries, in that it does not directly report to the Prime Minister at the cabinet level, nor is it affected by legislation that establishes it as an Independent Administrative Institution.

Chiyoda (千代田, Chiyoda) is a district of Chiyoda, Tokyo, Japan. In Japanese it translates as a "field of a thousand generations" Chiyoda covers the grounds of the Imperial Palace, and nothing else. It does not have any subdivisions, and no chome or postal code designation. The address of the palace itself and of the Imperial Household Agency is Chiyoda 1-1, the address of the Hospital of the Imperial Household is Chiyoda 1-2, the Imperial Guard Headquarters is Chiyoda 1-3. Its small population consists of Imperial guards and dependents. The Imperial family itself is not included in the registered population.

Kōjimachi (麹町 or 麴町) is a district in Chiyoda, Tokyo.

The Graduate School of International Corporate Strategy (大学院 国際企業戦略研究科, Daigakuin Kokusai Kigyō Senryaku Kenkyūka), also known as Hitotsubashi ICS, is the graduate business school of Hitotsubashi University in Tokyo, Japan. Hitotsubashi ICS was the first "professional graduate school" (formerly "specialized graduate school") established in Japan. The school was founded by Harvard Business School professor Hirotaka Takeuchi, its first dean, in 1998, and admitted students in 2000. ICS is housed in the National Center of Sciences and located at Chiyoda Campus, the birthplace of Hitotsubashi University, Chiyoda, Tokyo.

The National Institute of Informatics (国立情報学研究所, Kokuritsu Jōhōgaku Kenkyūjo, NII) is a Japanese research institute located in Chiyoda, Tokyo, Japan. NII was established in April 2000 for the purpose of advancing the study of informatics. This institute also works on creating systems to facilitate the spread of scientific information to the general public. It oversees and maintains a large, searchable information database on a variety of scientific and non-scientific topics called Webcat. NII is the only comprehensive research institute in informatics in Japan. It is a major part of the Graduate University for Advanced Studies, SOKENDAI, and since 2002 has offered a Ph.D. program in informatics.