Facilities related to the Matsushiro
Imperial Headquarters

ToyonoObuseTsusumi V.

Obuse V.
⑤⑧ Imoi V. Nagano District CommandMatsukawa River卍 Zenkoji Tem.
Susobana River

Nagano Dentetsu Line

④Suzaka

Suzaka T.
Nagano⑥Amori V.

Nagano C.

Mamejima V.
Nagano Airfield

etsu

Line

Niigata Pr

Shin

Toyama Pr.

nino
Sh

maik uCh

ine

RivGunma
Pr.

Gifu Pr.

er

Nagano Pr.
Matsushiro T.

⑦①⑨ Kiyono V.

③

Amenomiya-agata V.

Yashiro T.

Nagano C.

Matsushiro

Shinonoi

Loi

The Matsushiro Imperial Headquarters

NaganoSai River

Kawanaka-jima

Dodo RiverDentetsuLine⑫Yashiro⑪②⑩

Yamanashi Pr.

Higashijo V.

Toyosaka V.

Nishijo V.

Shizuoka Pr.

Aichi Pr.

01

2

3

45km

Overview of the construction
warehouse names

location① “i”storehouse
Matsushiro T.
② “ro”storehouse Nishijo V.
③ “ha”storehouse Toyosaka V.
④ “ni”storehouse Suzaka T.
⑤ “ho”storehouse Tsusumi V.
⑥ “he”storehouse Suzaka T.
⑦ “to”storehouse Kiyono V.
⑧ “chi”storehouse Imoi V.
⑨ “ri”storehouse Amenomiya V.
⑩ temporary
Nishijo V.
Imperial Palace⑪ “kashiko-dokoro” Nishijo V.
⑫ Navy tunnel
Amori V.

construction
order date1944.10.4
1944.10.4
1944.10.4
1945.3.23
1945.6.8
1945.6.8
1945.3.23
1945.7.12
1945.7.12
1945.3.23
1945.7.12
1945.6.23

usage

the government. NHK. telephone station
the Imperial Headquarters
food storage
broadcasting facility for sending
broadcasting facility for sending
broadcasting facility for sending
broadcasting facility for receiving
the prince, the empress motherprinting bureau
the emperor and empress, Ministry of theImperial Householda palace sanctuary
Ministry of the Navy, Imperial JapaneseArmy General Staff

NPO法人

松代大本営平和祈念館

NPO Matsushiro Peace Museum
MatsushiroPeaceMuseum

1461 Matsushiro Matsushiro-machi Nagano-shi,
Nagano-ken 381-1231, Japantel 026-214-1557 fax 026-262-1831

●What is “Daihon'ei” ?
“Daihon’ei” was the supreme headquarters under the supervision of theEmperor, the Supreme Commander of theJapanese Army and Navy. It commanded
Japan's armed forces in times of war, set
the strategy for the Army and the Navy,and issued orders to the soldiers.
When the Japanese army fought anddefeated the enemy, the Imperial Headquarters exaggerated the accomplishment,
and when the Japanese army lost andsuffered damage, it did not report it at all.
Thus, Daihon’ei hid the true nature of thewar and encouraged the people to go towar.

●Why was Matsushiro in Shinshu(Nagano Prefecture) chosen?
1. Geographical reason: it was neither too far nor too close to the capital Tokyo,
and an airport was located nearby.
2. Geological reason: it had hard, solid bedrock that could withstand the bombsof enemy air raids.
3. Topographical reason: it is in a basin surrounded by mountains, making it
difficult to bomb. Also, there is enough area to build vast facilities
underground.
4. Mobilization: Shinshu(Nagano Prefecture) had a comparatively abundant labor
force for the construction work.
5. Name Shinshu: The word Shinshu (信州), or the old name of Nagano
Prefecture, is read in the same way as another Shinshu(神州), or the land ofGod. The name has a dignity and nuance suitable for the relocation of theemperor.

●What was the decisive battle on the mainland?
In 1944, the Japanese military, having lost control of theseas and air, decided to fight the "decisive battle on themainland.” In July of the same year, the U.S. military
succeeded in establishing bases for B-29 bombers on thePacific island of Saipan and other locations. From Januaryof the following year, not only military facilities throughout
Japan but also all large and medium-sized cities werethoroughly bombed indiscriminately.
The people lived in fear of the air raids almost everynight. In preparation for the "Hondo Kessen," or thedecisive battle on the mainland, even women and children
were trained to fight with bamboo spears instead ofweapons, being told to be the last person standing; in otherwords, to sacrifice their lives for the Emperor.

●Why was a large bunker dug in Matsushiro?

●Who dug the tunnels?

●How was Matsushiro related to Okinawa?

Around the end of the Asia Pacific War, Japan had little chance of winning the war
against the United States, the UK, China, and other allied nations. The Imperial
Headquarters was located in the Imperial Palace in the capital city of Tokyo, but as air
raids on the mainland were imminent, it was decided to move the headquarters to a safer
location in the countryside. It was planned that the emperor, the military, and government
officials would be able to stay in underground tunnels and continue to lead the war.
The government, NHK (Japan Broadcasting Corporation), and the Central Telephone
Station were to be built underneath Mt. Zozan, the Imperial Headquarters and temporary
Imperial Palace were to be built underneath Mt. Maizuru, and an area for food storage wasto be built underneath Mt. Minakami. Those were all planned for the protection of Japan’snational polity.
Preparations began in 1944, and construction began on November 11 of that year. Theconstruction of the tunnel leading to a ‘warehouse’ was carried out, and the fact that it
was for "the Imperial Headquarters" was a top secret. It was about 80-90% complete innine months, but construction was halted in August 1945 when Japan lost the war.

Many Japanese and Koreans
were recruited to dig the tunnels.
Around 6,500 Koreans, including
those forcibly brought from theKorean peninsula, then Japan'scolony, were forced to live in
unsanitary houses in Matsushirowith no freedom. They wereforced to do dangerous work dayand night. It is estimated that inApril 1945, about 10,000 people
were involved in the construction
work, including Labor ServiceCorps and school children.

On April 1, 1945, the U.S. troops landed on the mainisland of Okinawa, and the only ground battle in Japan
involving noncombatant residents went on until June 23 (nowOkinawa Memorial Day), where a quarter of the prefecture's
population were killed. It is said that this three-month battle
was a way to buy time to prepare for the eventual battle on
the mainland, and the time for the completion of the tunnels
at Matsushiro.
The Potsdam Declaration was issued on July 26, forcing
Japan to surrender unconditionally, but the Japanese
government ignored it and continued the war. An atomic
bomb was dropped on Hiroshima on August 6 and on
Nagasaki on the 9 respectively, and the Soviet Union joined
the war. On August 14, Japan finally accepted the Potsdam
Declaration, and the next day on August 15 the Emperor
announced the end of the war to the nation with a radio
broadcast called the Emperor's address.