Yokosuka Naval Air Technical Arsenal

Order of Battle · Aircraft manufacturers · Japan

Yokosuka Naval Air Technical Arsenal

Kaigun Kōkū Gijutsu-shō (Kūgi-shō) · Kaigun Kōkūshō (Naval Air Arsenal) · Yokoshō

The Imperial Japanese Navy’s own design bureau drew the fastest dive-bomber of the war, the only aircraft to bomb mainland America, and the Ohka rocket bomb, and left others to build most of them.

1913Founded
Defunct 1945Status
7Aircraft on record
1Air forces flying its types
Photo: Wikimedia Commons (Public domain)
CountryJapanFounded1913HeadquartersYokosuka, KanagawaStatusDefunct 1945
The story

Yokosuka Naval Air Technical Arsenal: the company and the aircraft that made its name

The navy designs its own

The arsenal began in May 1913 as an aeroplane factory in the navy’s ordnance department at Yokosuka, on Tokyo Bay, and went through a string of names before becoming the Naval Air Arsenal on 1 April 1932, known as Kūgi-shō. It was the navy’s own research and design centre, and many of its designs were built in quantity by private firms. Its K5Y trainer, the orange-painted Red Dragonfly of 1933, ran to 5,770 aircraft from several makers.

Bombs on Oregon

Its E14Y submarine floatplane, of which 126 were built, has a unique distinction. On 9 September 1942 Nobuo Fujita launched from submarine I-25 off Brookings, Oregon, and dropped incendiary bombs on the forest — the only time an Axis aircraft bombed the continental United States. They did no real damage. The D4Y Suisei, first flown in December 1940 and built mostly by Aichi, was called the fastest dive-bomber of the war; 2,038 were made. The P1Y Ginga bomber, 1,002 built by Nakajima, was shaped by Tadanao Miki, who later worked on the aerodynamics of the first Shinkansen bullet trains.

The Ohka and the end

The arsenal’s most notorious design was the MXY7 Ohka, a rocket-powered piloted bomb conceived by Ensign Mitsuo Ohta and carried under a G4M bomber. Its first combat mission on 21 March 1945 was a failure; on 12 April it sank USS Mannert L. Abele. Some 852 were built, 155 at Yokosuka. On 15 August 1945, hours after the surrender broadcast, Admiral Ugaki led eleven D4Ys on a final suicide mission. The arsenal ended with the navy that owned it.

The Imperial Japanese Navy’s own design bureau drew the fastest dive-bomber of the war, the only aircraft to bomb mainland America, and the Ohka rocket bomb, and left others to build most of them.Yokosuka Naval Air Technical Arsenal · verified 2026-10-03
At a glance

Yokosuka Naval Air Technical Arsenal in numbers

The company

In short
Founded 1913

  • Imperial Japanese Navy research and design arsenal at Yokosuka
  • Known as Kūgi-shō from 1932
  • Designs mostly mass-produced by private firms

Production

Best known for
D4Y Suisei, P1Y Ginga, Ohka

  • K5Y trainer: 5,770 built
  • D4Y: 2,038 built
  • MXY7 Ohka: 852 built

Today

Now
Ended 1945

  • Abolished with the Imperial Japanese Navy

The numbers

K5Y trainers built (all makers)
5,770
D4Y Suisei built
2,038
P1Y Ginga built
1,002
MXY7 Ohka built
852
E14Y built
126
The aircraft

Every notable Yokosuka Naval Air Technical Arsenal aircraft

Yokosuka P1Y GingaLand-based bomber · first flight 1943 · 1,002 built

Photos: Imperial Japanese Navy · public domain (Wikimedia Commons)

Aircraft Role First flight Built Status Note
Yokosuka K5Y Intermediate trainer 1933 5,770 Retired Red Dragonfly; a K5Y sank USS Callaghan on 28 July 1945
Yokosuka B4Y Carrier torpedo bomber 1936 Retired
Yokosuka H5Y Flying boat 1939 Retired
Yokosuka E14Y Submarine-borne reconnaissance floatplane 1939 126 Retired Bombed Oregon, 9 September 1942
Yokosuka D4Y Suisei Carrier dive-bomber 1940 2,038 Retired Built mainly by Aichi
Yokosuka P1Y Ginga Land-based bomber 1943 1,002 Retired Built by Nakajima; night-fighter P1Y2-S
Yokosuka MXY7 Ohka Rocket-powered piloted suicide bomb 1944 852 Retired Unpowered trials March 1944; powered November 1944
Who flies them

Yokosuka Naval Air Technical Arsenal aircraft in the world’s air forces

1 air forces in the Order of Battle fly or flew Yokosuka Naval Air Technical Arsenal types. 0 of them still have one in service.

Air force In service Formerly flown
Indonesian Air Force Yokosuka K5Y ‘Cureng’ and other ex-Japanese aircraft
Places, people, records

Where Yokosuka Naval Air Technical Arsenal built, who led it, what it achieved

Factories

  • Yokosuka arsenal · Yokosuka, Tokyo Bay — Temporarily at Tsukiji in 1923; 155 Ohka built here

People

  • Mitsuo Ohta · naval ensign — Conceived the Ohka in 1943
  • Tadanao Miki · engineer — Shaped the P1Y; later applied the ideas to early Shinkansen trains
  • Nobuo Fujita · pilot — Flew the E14Y raid on Oregon, 1942

Records and firsts

  • Only Axis aircraft to bomb the continental United States: E14Y over Oregon, 9 September 1942
  • D4Y described as the fastest dive-bomber of the Second World War
Timeline

Yokosuka Naval Air Technical Arsenal, year by year

1913

Aeroplane factory established in the navy ordnance department

1919

Becomes the Naval Establishment for Aeronautical Research

1923

Temporary move to Tsukiji, destroyed in the Great Kanto earthquake

1932

Becomes the Naval Air Arsenal (Kūgi-shō)

1933

K5Y trainer

1940

D4Y first flight

1941

E14Y reconnoitres Pearl Harbor after the attack

1942

E14Y bombs the Oregon forest

1943

P1Y first flight

1945

First Ohka combat mission

1945

Ohka sinks USS Mannert L. Abele

1945

Ugaki’s final D4Y mission

Questions & Answers

Everything people ask about Yokosuka Naval Air Technical Arsenal

What was the Yokosuka Naval Air Technical Arsenal?
The Imperial Japanese Navy’s own aircraft research and design establishment at Yokosuka, founded in 1913 and known as Kūgi-shō.
Did a Japanese plane bomb the United States?
Yes. On 9 September 1942 a Yokosuka E14Y launched from submarine I-25 dropped incendiary bombs near Brookings, Oregon, causing no real damage.
What was the Ohka?
A rocket-powered piloted suicide bomb, the MXY7, carried under a bomber; 852 were built and it sank USS Mannert L. Abele in April 1945.
Who built Yokosuka-designed aircraft?
Many were mass-produced by private firms: the D4Y mainly by Aichi, the P1Y by Nakajima and the K5Y by several makers.

Continue the tour

Around Yokosuka Naval Air Technical Arsenal

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Sources & Further Reading

Every fact, checked

Verified 2026-10-03.