The otherwise known as the "Circle Two" Plan was the second of four expansion plans of the

Imperial Japanese Navy The Imperial Japanese Navy (IJN; Kyūjitai: Shinjitai: ' 'Navy of the Greater Japanese Empire', or ''Nippon Kaigun'', 'Japanese Navy') was the navy of the Empire of Japan from 1868 to 1945, when it was dissolved following Japan's surrender ...

between 1930 and the start of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...

Background

The

London Naval Treaty The London Naval Treaty, officially the Treaty for the Limitation and Reduction of Naval Armament, was an agreement between the United Kingdom, Japan, France, Italy, and the United States that was signed on 22 April 1930. Seeking to address is ...

placed severe restrictions on Japan's naval capabilities vis-a-vis the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

and the British

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against Fr ...

in terms of tonnage and numbers of capital warships. The response of the

Imperial Japanese Navy General Staff The was the highest organ within the Imperial Japanese Navy. In charge of planning and operations, it was headed by an Admiral headquartered in Tokyo. History Created in 1893, the Navy General Staff took over operational (as opposed to adminis ...

was to initiate a construction program to build new warships to the allotted tonnage limits in each of the restricted categories, and to invest in types of warships and weaponry not specifically covered by the provisions of the treaty.Evans, ''Kaigun''. pp. 238–239 The "Circle One" plan was submitted by the Naval Ministry and approved by the

Cabinet Cabinet or The Cabinet may refer to: Furniture * Cabinetry, a box-shaped piece of furniture with doors and/or drawers * Display cabinet, a piece of furniture with one or more transparent glass sheets or transparent polycarbonate sheets * Filin ...

in November 1930, and officially ratified by the

Diet of Japan The is the national legislature of Japan. It is composed of a lower house, called the House of Representatives (, ''Shūgiin''), and an upper house, the House of Councillors (, '' Sangiin''). Both houses are directly elected under a paral ...

in 1931. It called for the construction of 39 new combat vessels, centering on four of the new s, and expansion of the

Imperial Japanese Navy Air Service The was the air arm of the Imperial Japanese Navy (IJN). The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War. The Japanese military acquired their first aircraft in 1910 ...

to 14 Naval Air Groups. However, plans for a second expansion budget were delayed by the ''Tomozuru'' Incident and IJN 4th Fleet Incident, when it was revealed that the basic designs of many Japanese warships were flawed due to poor construction techniques and instability caused by attempting to mount too much weaponry on too small a displacement hull. As a result, most of the naval budget in 1932–1933 was absorbed in modifications to rectify issues with existing equipment. In 1934, the Naval Ministry submitted its second expansion plan to the Cabinet and Diet for approval. This plan was a multiyear (four year) budget, covering the construction of 48 new warships and creation of eight new Naval Air Groups. A total of 431,680,800 Yen was allotted for warship construction and 33,000,000 Yen for

naval aviation Naval aviation is the application of military air power by navies, whether from warships that embark aircraft, or land bases. Naval aviation is typically projected to a position nearer the target by way of an aircraft carrier. Carrier-based ...

Table of vessels

Notes

References

* {{IJN Naval Armnament Supplement Programs Naval Armaments Supplement Programme Naval Armaments Supplement Programme

Background

Table of vessels

See also

Notes

References