2nd Naval Armaments Supplement Programme

The response of the Imperial Japanese Navy General Staff 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.

[1] The "Circle One" plan was submitted by the Naval Ministry and approved by the Cabinet in November 1930, and officially ratified by the Diet of Japan in 1931.

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.

This plan was a multiyear (four year) budget, covering the construction of 48 new warships and creation of eight new Naval Air Groups.