In the Meiji period, most structures from the Edo Castle disappeared.
Some were cleared to make way for other buildings while others were destroyed by earthquakes and fire.
For example, the wooden double bridges (二重橋, Nijūbashi) over the moat were replaced with stone and iron bridges.
The buildings of the Imperial Palace constructed in the Meiji era were constructed of wood.
Their design employed traditional Japanese architecture in their exterior appearance while the interiors were an eclectic mixture of then-fashionable Japanese and European elements.
The ceilings of the grand chambers were coffered with Japanese elements; however, Western chairs, tables and heavy curtains furnished the spaces.
The floors of the public rooms had parquets or carpets while the residential spaces used traditional tatami mats.

The main audience hall was the central part of the palace.
It was the largest building in the compound.
Guests were received there for public events.
The floor space was more than 223 tsubo or approximately 737.25 m² (7,935.7 sq ft).
In the interior, the coffered ceiling was traditional Japanese-style, while the floor was parquetry.
The roof was styled similarly to the Kyoto Imperial Palace, but was covered with (fireproof) copper plates rather than Japanese cypress shingles.

In the late Taishō and early Shōwa period, more concrete buildings were added, such as the headquarters of the Imperial Household Ministry and the Privy Council.
These structures exhibited only token Japanese elements.

From 1888 to 1948, the compound was called Palace Castle (宮城, Kyūjō).
On the night of 25 May 1945, most structures of the Imperial Palace were destroyed in the Allied firebombing raid on Tokyo.
According to the US bomber pilot Richard Lineberger, Emperor's Palace was the target of their special mission on July 29, 1945, and was hit with 2000-pound bombs.
In August 1945, in the closing days of World War II, Emperor Hirohito met with his Privy Council and made decisions culminating in the surrender of Japan at an underground air-raid shelter on the palace grounds referred to as His Majesty's Library (御文庫附属室, Obunko Fuzokushitsu).

Due to the large-scale destruction of the Meiji-era palace, a new main palace hall (宮殿, Kyūden) and residences were constructed on the western portion of the site in the 1960s.
The area was renamed Imperial Residence (皇居, Kōkyo) in 1948, while the eastern part was renamed East Garden (東御苑, Higashi-Gyoen) and became a public park in 1968.

Interior images of the old Meiji-era palace
In the Meiji period, most structures from the Edo Castle disappeared. Some were cleared to make way for other buildings while others were destroyed by earthquakes and fire. For example, the wooden double bridges (二重橋, Nijūbashi) over the moat were replaced with stone and iron bridges. The buildings of the Imperial Palace constructed in the Meiji era were constructed of wood. Their design employed traditional Japanese architecture in their exterior appearance while the interiors were an eclectic mixture of then-fashionable Japanese and European elements. The ceilings of the grand chambers were coffered with Japanese elements; however, Western chairs, tables and heavy curtains furnished the spaces. The floors of the public rooms had parquets or carpets while the residential spaces used traditional tatami mats.
The main audience hall was the central part of the palace. It was the largest building in the compound. Guests were received there for public events. The floor space was more than 223 tsubo or approximately 737.25 m² (7,935.7 sq ft). In the interior, the coffered ceiling was traditional Japanese-style, while the floor was parquetry. The roof was styled similarly to the Kyoto Imperial Palace, but was covered with (fireproof) copper plates rather than Japanese cypress shingles.
In the late Taishō and early Shōwa period, more concrete buildings were added, such as the headquarters of the Imperial Household Ministry and the Privy Council. These structures exhibited only token Japanese elements.
From 1888 to 1948, the compound was called Palace Castle (宮城, Kyūjō). On the night of 25 May 1945, most structures of the Imperial Palace were destroyed in the Allied firebombing raid on Tokyo. According to the US bomber pilot Richard Lineberger, Emperor's Palace was the target of their special mission on July 29, 1945, and was hit with 2000-pound bombs. In August 1945, in the closing days of World War II, Emperor Hirohito met with his Privy Council and made decisions culminating in the surrender of Japan at an underground air-raid shelter on the palace grounds referred to as His Majesty's Library (御文庫附属室, Obunko Fuzokushitsu).
Due to the large-scale destruction of the Meiji-era palace, a new main palace hall (宮殿, Kyūden) and residences were constructed on the western portion of the site in the 1960s. The area was renamed Imperial Residence (皇居, Kōkyo) in 1948, while the eastern part was renamed East Garden (東御苑, Higashi-Gyoen) and became a public park in 1968.
Interior images of the old Meiji-era palace
Tokyo Imperial Palace