On 27th December 1922 the Japanese aircraft carrier Hōshō is commissioned. Not only was this the first aircraft carrier of the Imperial Japanese Navy, but it was also the first purpose built aircraft carrier in the world.

The extract and photos below are both taken from New Vanguard 109: Imperial Japanese Navy Aircraft Carries 1921–45 by Mark Stille. 

hosho aircraft

Hōshō in October 1945 after its surrender

Design and Construction.  The Imperial Navy’s first carrier was not the first ship to be designed as a carrier from the keel up, as is often stated. Hosho was laid down as a mixed seaplane carrier/aircraft carrier employing both seaplanes and deck-launched aircraft. The ship was modified during construction and was completed as a full-deck aircraft carrier based on a light cruiser hull. She was launched in November 1921 and commissioned into service in December 1922. With a narrow beam and a 300ft hangar, only 21 aircraft could be carried. This was later reduced to 11 as aircraft got larger.

Service Modifications.  The most obvious modification occurred early in Hosho’s career. A small starboard-side island was found to impede aircraft operations on such a narrow deck and was removed. Navigation was now accomplished from two platforms mounted on either side of the forward edge of the hangar. During the Pacific War, Hosho was relegated to secondary duties in home waters and was therefore only slightly modified. The flight deck was lengthened and widened in 1944 to facilitate its role as a training carrier.

hosho inside

View from the forecastle of Hōshō after its surrender

Armament. When completed in 1922, little consideration was given to anti-aircraft defense, and the ship was equipped for defense primarily against surface attack. Accordingly, four 5.5in guns were mounted outboard of the hangar and two 3in AA guns were positioned on the flight deck. As war neared, only the 3in guns remained; these were removed at the start of the war, and eight 25mm AA guns were fitted. The number of 25mm guns was increased to 30 by 1944. When surrendered in 1945, only six 25mm guns remained.

Operational History. During the Sino-Japanese War of 1937–40, Hosho was active in operations off the China coast. Of marginal usefulness by the opening of the Pacific War in 1941, Hosho was employed in a few minor operations before she participated in the battle of Midway as an escort to the battleship-heavy Main Body. Afterwards, Hosho returned to the Inland Sea and was used as a training carrier for the remainder of the war. Hosho survived the war and was used for repatriation duties before being scrapped in 1947.”

If you’d like to read more about the Imperial Japanese Navy take a look at New Vanguard 109: Imperial Japanese Navy Aircraft Carries 1921–45 and New Vanguard 232: The Imperial Japanese Navy of the Russo-Japanese War, both by Mark Stille.