| Fleet Faction | |
|---|---|
| 艦隊派 | |
 Admiral Katō Kanji, who led opposition to the Washington Naval Treaty, was regarded as the leader of the faction. | |
| Also known as | Kantaiha |
| Foundation | 1920s |
| Dissolved | c. 1940 |
| Motives | Increasing the size of the Imperial Japanese Navy |
| Active regions | Japan |
| Ideology | Militarism, nanshin-ron |
| Opponents | Treaty Faction |
The Fleet Faction (Japanese: 艦隊派, romanized: kantai-ha) was an informal political faction within the Imperial Japanese Navy active in the 1920s and 1930s. The kantai-ha sought to drastically increase the size of the Imperial Japanese Navy in order to reach force parity with the fleets of the United States Navy and Royal Navy in the Western Pacific Ocean. The group advocated for the kantai kessen, a doctrine specifying a need for larger warships and larger-caliber guns.
Opposition to the Washington Naval Treaty led to the formation of the Fleet Faction, which was led by Admiral Kato Kanji. The Fleet Faction was formed in reaction to the Treaty Faction, who had successfully negotiated the terms of the treaty. The treaty would lead to increasing militancy and opposition to the established naval staff, who were seen as defeatists and endangering Japanese national security. Further opposition to the Geneva Naval Conference and London Naval Treaty fueled increasingly hawkish demands for naval expansion by the kantai-ha, leading to a split between junior and senior naval officers in the Navy Ministry. During the rise of statism in Shōwa Japan, the Fleet Faction consolidated power in a series of purges and political violence against treaty proponents, eventually resulting in the abrogation and denunciation of the Washington Treaty by Japan in 1934 and Japan's withdrawal from the Second London Naval Treaty conference in 1936.