Editing Japanese aircraft carrier Hiryū (section)

===Indian Ocean Raid===
{{main|Indian Ocean Raid}}
On 26 March, the five carriers of the First Air Fleet departed from Staring Bay; they were spotted by a Catalina about {{convert|350|nmi}} southeast of [[Ceylon]] on the morning of 4 April. Six of ''Hiryū''{{'}}s Zeros were on [[Combat Air Patrol]] (CAP) and helped to shoot it down. Nagumo closed to within {{convert|120|nmi}} of [[Colombo]] before launching an airstrike the next morning. ''Hiryū'' contributed 18 B5Ns and 9 Zeros to the force; the latter encountered a flight of 6 [[Fairey Swordfish]] torpedo bombers from [[788 Naval Air Squadron]] en route and shot them all down without loss. The Japanese aircraft encountered defending [[Hawker Hurricane]] fighters from [[No. 30 Squadron RAF|Nos. 30]] and [[No. 258 Squadron RAF|258 Squadrons RAF]] over [[Ratmalana International Airport|Ratmalana]] airfield and ''Hiryū''{{'}}s fighters claimed to have shot down 11 with 3 Zeros damaged, although the fighters from the other carriers also made claims. British losses were 21 Hurricanes shot down and 2 more forced to crash land. The D3As and B5Ns inflicted some damage to the port facilities, but a day's warning had allowed much of the shipping in the harbor to be evacuated. The British were attempting to find Nagumo's ships all morning and ''Hiryū''{{'}}s Zeros on CAP over the fleet helped to shoot down an [[Royal Air Force|RAF]] Catalina, shot down a [[Fairey Albacore]] torpedo bomber and drove off another from the carrier {{HMS|Indomitable|92|2}}. Later that morning the British [[heavy cruiser]]s {{HMS|Cornwall|56|2}} and {{HMS|Dorsetshire|40|2}} were spotted and ''Hiryū'' launched 18 D3As. They sank both ships in combination with the dive bombers from the other carriers.<ref>Shores, Cull & Izawa, Vol. II, pp. 393–406</ref>

On the morning of 9 April, ''Hiryū''{{'}}s CAP shot down another Catalina attempting to locate the fleet and, later that morning, contributed 18 B5Ns, escorted by 6 Zeros, to the [[Easter Sunday Raid#The attack on Trincomalee Harbour|attack on Trincomalee]]. The fighters engaged [[No. 261 Squadron RAF|261 Squadron RAF]], claiming to have shot down two with two more shared with fighters from the other carriers. British losses were only eight fighters, but the Japanese pilots claimed a total of 49 aircraft shot down when the RAF only had 16 Hurricanes in the fight. The British pilots shot down one of ''Hiryū''{{'}}s B5Ns and forced another to crash land while they were bombing the port. Meanwhile, a [[floatplane]] from the battleship {{ship|Japanese battleship|Haruna||2}} spotted the small aircraft carrier {{HMS|Hermes|95|2}}, escorted by the destroyer {{HMAS|Vampire|D68|6}}, and every available D3A was launched to attack the ships, escorted by nine Zeros. ''Hiryū'' contributed 18 dive bombers and 3 fighters, but they arrived too late to assist in sinking them and found two other ships further north. They sank the freighter RFA ''Athelstone'' and her escorting [[corvette]], {{HMS|Hollyhock|K64|2}}. While this was going on, ''Akagi'' narrowly escaped damage when 9 British [[Bristol Blenheim]] bombers from Ceylon penetrated the CAP and dropped their bombs from {{convert|11000|ft|m}}. ''Hiryū'' had eight Zeros aloft, along with 12 more from the other carriers, and collectively they accounted for 5 of the British bombers for the loss of 1 of ''Hiryū''{{'}}s Zeros. The Blenheims ran into the D3As from {{ship|Japanese aircraft carrier|Shōkaku||2}}, escorted by ''Hiryū''{{'}}s Zeros, on their way back home and lost one more bomber to the Japanese aircraft. The dive bombers claimed to have shot down two Blenheims in conjunction with the Zeros, which claimed one on their own, for the loss of one Zero shot down by the bombers' gunners and one D3A damaged. After launching the dive bombers that sank ''Hermes'' and the other ships, the First Air Fleet reversed course and headed southeast for the [[Malacca Strait]] and Japan.<ref>Shores, Cull & Izawa, Vol. II, pp. 413, 421–423, 426–429</ref>

On 19 April, while transiting the [[Bashi Straits]] between Taiwan and [[Luzon]] en route to Japan, ''Hiryū'', ''Sōryū'', and ''Akagi'' were sent in pursuit of the American carriers {{USS|Hornet|CV-8|2}} and {{USS|Enterprise|CV-6|2}}, which had launched the [[Doolittle Raid]] against Tokyo. They found only empty ocean, as the American carriers had immediately departed the area to return to Hawaii. The carriers quickly abandoned the chase and dropped anchor at [[Hashirajima]] anchorage on 22 April. Having been engaged in constant operations for four and a half months, the ship, along with the other three carriers of the First and Second Carrier Divisions, was hurriedly refitted and replenished in preparation for the [[Combined Fleet]]'s next major operation, scheduled to begin one month hence.<ref>Parshall & Tully, p. 12</ref> While at Hashirajima, ''Hiryū''{{'}}s air group was based ashore at Tomitaka Airfield, near [[Saiki, Ōita]], and conducted flight and weapons training with the other First Air Fleet carrier units.<ref>Parshall & Tully, pp. 10, 42, 88</ref>