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.

Tokugawa Ieyasu made Edo Castle his base after he was offered eight eastern provinces by Toyotomi Hideyoshi.

[1] He later defeated Toyotomi Hideyori, son of Hideyoshi, at the Siege of Osaka in 1615, and emerged as the political leader of Japan.

Those who did not supply stones were required to contribute labor for such tasks as digging the large moats and flattening hills.

Various fires over the centuries damaged or destroyed parts of the castle, Edo and the majority of its buildings being made of timber.

On April 21, 1701, in the Great Pine Corridor (Matsu no Ōrōka) of Edo Castle, Asano Takumi-no-kami drew his short sword and attempted to kill Kira Kōzuke-no-suke for insulting him.

In the year Meiji 2 (1868), on the 23rd day of the 10th month of the Japanese calendar the emperor moved to Tokyo and Edo castle became an imperial palace.

The area around the old keep, which burned in the 1657 Meireki fire, became the site of the new Imperial Palace Castle (宮城, Kyūjō), built in 1888.

The government declared the area an historic site and has undertaken steps to restore and preserve the remaining structures of Edo Castle.

[9] With the enforcement of the sankin-kōtai system in the 17th century, it became expedient for the daimyōs to set up residence in Edo close to the shōgun.

[10] Daimyōs with lesser wealth were allowed to set up their houses, called banchō, to the north and west of the castle.

Edo Castle was protected by multiple large and small wooden gates (mon), constructed in-between the gaps of the stone wall.

As noted by Caron, the gate consisted of a square-shaped courtyard or enclosure and a two-story gatehouse which is entered via three roofed kōrai-mon.

[11] All major gates had large timbers that framed the main entry point and were constructed to impress and proclaim the might of the shogunate.

The Spanish Governor-General of the Philippines Rodrigo de Vivero y Velasco gave an eye-witness account in 1608–1609, describing the huge stones that made up the walls and a large number of people at the castle.

It consisted of a series of low-level buildings, connected by corridors and congregating around various gardens, courtyards or lying detached, similar to the structures that can be seen in Nijō Castle in Kyoto today.

The other remaining keeps are Fushimi-yagura (next to the upper steel bridge of Nijūbashi) and Tatsumi-nijyu-yagura (at the corner of Kikyō-bori moat next to Kikyō-mon gate).

About 150–160 meters (490–520 ft) north of the Fujimi-yagura is the former site of the Matsu no Ōrōka corridor, scene of dramatic events in 1701 that led to the forty-seven rōnin incident.

This defense house sits on top of the large stone walls overlooking to the Hasuike-bori (Lotus-growing moat).

During the Edo period, double and triple keeps (yagura) were constructed at strategic points on top of the stone wall surrounding the Honmaru.

Shiomi-zaka (潮見坂) is a slope running alongside today's Imperial Music Department building towards Ninomaru enceinte.

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 shōguns was constructed in 1639 in the west area (Western Perimeter) and in 1630 it is reported that a garden designed by Kobori Enshū, who was the founder of Japanese landscaping, was to its south-east.

As the Honmaru enceinte was said to begin right behind the Naka-no-mon gate, the Ō-bansho probably played a key role in the security of Edo Castle.

A steep slope, Bairin-zaka (梅林坂), runs from eastern Honmaru toward Hirakawa-mon in front of the today's Archives and Mausolea Department building.

Several repairs were conducted after the Meiji era, but the damage caused by the September 1923 Great Kantō earthquake lead to the dismantling of the watari-yagura (渡り櫓) and rebuilding of the stone walls on each side of the gate in 1925.

The Nishinomaru is bordered by moats to the west such as the Dōkan-bori, Sakurada-bori and Gaisen-bori to the south, Kikyō-bori and Hamaguri-bori to the north.

Fushimi-yagura (伏見櫓) is a two-storey keep that still exists at the western corner leading towards the inner Nishinomaru, flanked by two galleries (tamon) on each side.

The Fukiage is encircled by the Dōkan-bori to the Nishinomaru to the east, the Sakurada-bori to the south, the Hanzō-bori to the west, the Chidorigafuchi to the northwest and the Inui-bori to the north.

Ōtemachi (大手町, "the town in front of the great gate"), Takebashi (竹橋, "the Bamboo Bridge"), Toranomon (虎ノ門, "the Tiger Gate"), Uchibori Dōri (内堀通り, "Inner Moat Street"), Sotobori Dōri (外堀通り, "Outer Moat Street"), and Marunouchi (丸の内, "Within the enclosure") are examples.