Short answers, pulled from the story.
The Imperial Japanese Navy was officially established in 1871 when the domains donated their forces to the central government. This centralization marked the institutional beginning of the navy after the domains were abolished altogether. The Ministry of War was replaced by a separate Navy Ministry in February 1872 to further consolidate control.
The Imperial Japanese Navy launched the Hosho in 1921 as the first purpose-built aircraft carrier in the world to be completed. This vessel was developed with influence from the British Sempill Mission which arrived in November 1921. The Hosho represented a key step in building an effective naval air force for the Imperial Japanese Navy.
Admiral Togo led the Imperial Japanese Navy to a decisive victory at the Battle of Tsushima in 1905. The Russian fleet was almost completely annihilated in this lopsided battle where 21 ships were sunk and 7 were captured. The Japanese lost only 116 men and three torpedo boats during the engagement.
The Imperial Japanese Navy subscribed to a doctrine of decisive battle known as Kantai Kessen. This strategy required the navy to comprehensively destroy the bulk of an enemy's naval strength in a single large-scale fleet action. The doctrine was derived from the writings of Satou Tetsutarou and influenced by Alfred T. Mahan.
The Imperial Japanese Navy was dissolved following Japan's surrender in World War II in 1945. The Japan Maritime Self-Defense Force was formed between 1952 and 1954 after the dissolution of the IJN. The navy had been the primary opponent of the Western Allies in the Pacific War before its end.