Upon completion, the Shokaku, became the most modern aircraft carrier in the IJN and one of the finest of her type in the world. Her engineers not only understood the need for extra aircraft storage spaces but also the need to quickly rotate them into action. Three elevators were included in the deck design, this facilitating movement of combat aircraft up and down from the hanger decks to the flight deck, allowing aircraft to be quickly refitted (refueled and rearmed) and launching. To help maintain morale of the hard-working crew, comfortable living spaces were constructed throughout the Flying Crane.
For defense against surface ships and incoming enemy aircraft, the Shokaku was armed with 8 x twin mounts of 16 x 5-inch guns and 36 x 25mm anti-aircraft cannons. By 1944, 96 x 25mm anti-aircraft cannons were added. Defensive armor allocation included 6.5-inches protecting magazine spaces and 3.9-inches for the deck. Machinery areas were given 5.1-inch armor protection. For offense, the Shokaku could carry up to 84 aircraft including 18 x Mitsubishi A6M "Zero" fighters, 27 x Aichi D3A "Val" dive bombers and 27 x Nakajima B5N "Kate" torpedo planes across two hangers. World War 2 ushered in the era of the aircraft carrier and these floating islands could now bring the fight to the enemy. Fighters served as air cover for the dive bombers and torpedo bombers, the latter forces used to directly attack surface vessels or land-based targets as needed.
The construction of both carrier ships was delayed for a time when the funnel arrangement was changed after completion. The funnels were moved directly aft of the island superstructure along the starboard side of the ship. Also, surviving crew members of the hapless IJN carrier Kaga - this vessel lost at the Battle of Midway - indicated that onboard fires had increased and spread beyond control due to the air spaces found around the fuel tanks. To counter this design fault in the new carriers, concrete was used to fill the air spaces. Shokaku was launched on June 1st, 1939, and was officially completed and formally commissioned on August 8th, 1941.
Five months before, on April 10th, the IJN had created the First Air Fleet - the Kido Butai or "Mobile Unit Force". It was comprised of all of Japan's fleet and light carriers supported by 474 aircraft, 2 battleships, 3 cruisers, 9 destroyers, 8 tankers, 23 submarines and 4 midget submarines. This historical military initiative was a new concept in naval aviation - essentially becoming the first tactical carrier task force. Now that Shokaku and her sister ship Zuikaku had finished their "shake down" cruises, they joined the other carriers of the Kido Butai - the Akagi, Kaga, Soryu and Hiryu. This carrier group, under Admiral Yamamoto, was training to carry out the upcoming raid that would bring the United States into World War 2 - the surprise attack on Pearl Harbor, Hawaii.
Japanese authorities felt that the nation was ready for all-out war. Her naval forces were far superior to that of any other nation in 1941, possessing ten aircraft carriers and 1,500 trained and tested aviators. Along with top quality surface ships, submarines and aviators they also possessed the best carrier-based fighter of the time in the Mitsubishi A6M "Zero" and the equally adept torpedo plane, the Nakajima B5N "Kate".
Attack at Pearl Harbor
In September of 1941, the Shokaku was sent to patrol with the 1st Air Fleet in the Kobe and Kure area within home waters. Her first captain, Yokokawa Ichibei, continued to train his ship's crew until they were called to duty with the Kido Butai. On November 26th, 1941 Shokaku and five other carriers with their support ships of the Japanese strike force departed Japan under radio silence and were at sea for twelve days, arriving some 200 miles off the coast of Oahu, Hawaii on December 7th, 1941 - ready to target and destroy the American carrier force thought stationed there. She joined her other carriers in launching a total of 408 aircraft - 360 to be used on the two attack waves against the harbor and 48 "Zero" fighters for air CAP (Combat Air Patrol) over the strike force. After the aircraft were recovered from the second attack wave, fleet commander Admiral Nagumo decided not to launch a third wave because it was found that the American carriers were not at Pearl at the time and an intact IJN fleet would be needed now more than ever. All-out war had commenced with a striking Japanese victory - and Shokaku had played her part.
The Kido Butai fleet, with Shokaku in tow, retired back across the Pacific towards Japan. On December 23rd, 1941 Shokaku was assigned to home waters by Hashirajima, Japan along with the carriers Akagi, and Kaga. On January 8th, 1942 Shokaku was ordered to proceed to the Pacific base at Truk Lagoon, this port serving as the major IJN anchorage in the Pacific. The base had five airstrips, a deep lagoon for anchored battleships, a torpedo boat station, submarine pens, a communications/radar center, troop facilities and coastal gun defenses, making her as important to the Japanese Navy as Pearl Harbor was to the US Navy.
Shokaku used Truk as her staging base when going on sorties as called upon. Word was received that an American carrier force was en route to the Marshall Islands to attack Japanese installations and local shipping. Shokaku and a destroyer screening force (consisting of Shiranuhi, Kasumi and Urakaze) were sent to counter the attack. The American force withdrew when challenged and was pursued by Shokaku and her destroyers. The American force ultimately escaped and Shokaku proceeded to the Japanese-held stronghold on the island of Palau. After returning to Truk, she was recalled to home waters in February 1942 and arrived at Yokosuka. At that point she was reassigned to Strike Force Main Body until March 15th.
Battle in the Indian Ocean
The Indian Ocean raid was a naval sortie by the Fast Carrier Strike Force of the Imperial Japanese Navy at the end of March through April 10th, 1942. This action targeted British shipping lanes and bases across the Indian Ocean. Shokaku, along with carriers Akagi, Zuikaku, Soryu and Hiryu, were assigned to the First Air Fleet, Division 5 and, on April 5th, 1942 she launched air strikes against British forces on Colombo. Two British cruisers, the HMS Cornwall and HMS Dorsetshire, were found at sea and were sunk by the IJN carrier force. The British forces at Trincomalee, Ceylon received radio traffic of the attacks and became concerned about the carrier HMS Hermes that was in port for repairs. The decision was made to move Hermes out to sea with a screen composed of the corvette HMS Hollyhock, the destroyer HMAS Vampire and two tankers. For whatever reason, the Hermes air arm was kept ashore. On April 9th the British squadron was attacked by 70 Japanese dive bombers from the IJN Division 5 carriers, including aircraft from Shokaku, resulting in the sinking of the Hermes after sustaining hits from no less than 40 bombs. She sank quickly along with 307 of her valiant crew. Also sunk by the IJN carrier aircraft were the corvette Hollyhock, the destroyer HMAS Vampire and the two tankers. If the Royal Navy 814 Squadron had been on Hermes at the time, perhaps some the Japanese attack aircraft could have been repulsed - however the battle was a great victory against the British fleet.
Battle of Coral Sea
Shokaku was reassigned to Truk to prepare for the upcoming sortie into the Coral Sea, this action code named "Operation MO". This was a joint Army and Navy operation to invade Port Moresby, New Guinea with troops and take Tulagi as a vital seaplane base. Covered by the light carrier Shoho, the fleet included three heavy cruisers, fourteen destroyers and several auxiliary ships protecting twelve transports housing 5,500 Japanese assault troops. Conquest of Moresby could potentially lead to air strikes against allied forces in the region and, perhaps more importantly, future attacks against Australian soil in preparation for a land invasion of the county. A Carrier Strike Force made up of the carriers Zuikaku and Shokaku, two heavy cruisers, and six destroyers steamed from Truk on May 1 as additional protection for the fleet. However, the American Navy and their team of specially trained code breakers soon deconstructed the Japanese J25 naval code. As such, the Americans had warning as to the Japanese intent and were alerted to the actions soon to come against Port Moresby. US Navy Admiral Chester Nimitz sent the Fleet carriers USS Yorktown (CV-5) and USS Lexington (CV-2) to the Coral Sea to position themselves in protection of Port Moresby. The American carriers were screened by nine cruisers, thirteen destroyers, a seaplane tender and one oiler.
On May 8th, 1942 aircraft from each side found the opposing carrier forces, beginning what would become the first carrier-versus-carrier battle in naval history as the "Battle of Coral Sea". The small Japanese carrier Shoho was sunk along with one destroyer and six small IJN ships received notable damage. The fleet carrier Shokaku was damaged by attacking American dive bombers, each hitting the carrier with 1,000-pound (454 kg) bombs. Two other dive bombers missed her and the Lexington's TBDs missed Shokaku with 11 torpedo attacks. However, Shokaku;s flight deck was seriously damaged in the action and 223 of her crew were either killed or wounded - it became painfully obvious to her captain that Shokaku was unable to conduct further aircraft operations. Captain Takatsugu Jojima requested permission from IJN headquarters at Takagi to withdraw from the battle. Orders were confirmed to Shokaku who subsequently retired to home waters, accompanied by a two-destroyer screen. The Japanese battle losses and damages numbered one light carrier, one destroyer, and three small warships along with one fleet carrier, one destroyer, two small warships and one transport damaged. In all, the Japanese carriers lost nine-two aircraft and a total of 966 pilots, air crew and IJN sailors killed in action. Carrier warfare had arrived.
USS Lexington was set on fire by a leak in her fuel lines that was caused from bomb damage and had to be scuttled by an American destroyer on May 8th, 1942. The majority of her pilots, air and ship's crew were saved because of sound firefighting tactics and enough time to transfer the men to awaiting destroyers. Aircraft were relocated to other carriers for reuse. These valuably trained men and stout aircraft would then later be reassigned to other carriers to fight another day. The American naval losses along with "Lady Lex" included one destroyer, an oiler that was mistaken for a carrier and the carrier USS Yorktown was damaged. A total of sixty-nine American aircraft were lost and 656 sailors were killed in action.
The outcome of the battle was in the favor of the Japanese but hindsight showed the Japanese lost 90 aircrew compared to 35 for the American carriers. This Japanese loss sounds relatively minimal based on scope, however, the training procedures for such pilots and aircrew were long and difficult, slowing replacements to the fleet. Conversely, American aircrews were being cranked out in training camps across the nation in something akin to an "assembly line" schedule. The short Battle of Coral Sea also helped the American Navy to hone in their tactics and defensive strategies for upcoming battles.
Shokaku, on her slow return, reached the repair yard at Kure, Japan, having almost capsized during the voyage home due to heavy seas and her battle damage suffered at Coral Sea. The IJN General Staff estimated that it would take two to three months to repair the vessel and replenish the carriers' air groups. So the battle damage from Coral Sea would keep both Shokaku and Zuikaku from participating in Yamamoto's upcoming Midway Island operation. As such, four available Japanese aircraft carriers now faced off against three American carriers instead of the planned six IJN carriers. The resulting actions at Midway was most detrimental to the Japanese. The news of the loss of four fleet Japanese carriers at Midway, along with some 248 aircraft, a heavy cruiser, plus 2,013 men killed that included many pilots and air crew, hit the Japanese military very hard - in much the way Pearl Harbor had hit the Americans.
Battle of the Eastern Solomons Islands
After repairs, Shokaku returned to the Pacific Campaign and joined what would become just the third carrier battle of World War 2 - the Battle of the Eastern Solomons Islands in August of 1942. Shokaku her sister ship as well as the light carrier Ryujo with two battleships, sixteen cruisers and twenty-five destroyers plus patrol ships and transports were sent to counter the Guadalcanal landings. The American landings were supported by three Task Forces - TF 11 USS Saratoga, TF 16 USS Enterprise and TF 18 USS Hornet. The IJN Operation Ka began on August 24th and 25th 1942. The light carrier Ryujo was sunk along with a destroyer, one troop transport and a light cruiser. A seaplane tender was damaged and the IJN carrier force lost another seventy-five aircraft and over 290 men. The American carrier USS Enterprise was damaged but no American ships were sunk and losses "only" totaled twenty-five aircraft with ninety men killed in action. Shokaku was not damaged and returned intact to Truk on September 5th, 1942. The battle resulted in yet another American victory and continued aircrew losses by the IJN.
Battle of the Santa Cruz Islands
Later in 1942, after Shokaku had been maintained and received new aircrews and aircraft, she took part in the IJN operation comprising the "Battle of the South Pacific" (or the "October Battle of the Santa Cruz Islands" as named by US Naval Operations CINCPAC). The battle, taking place on October 26th, 1942) was the fourth major naval engagement fought between the US Navy and the IJN - this particular one during the Guadalcanal campaign. Admiral Yamamoto felt he could make up for the IJN defeat at the Battle of Midway by engaging and destroying the US carriers at Guadalcanal utilizing Japanese carriers and supporting warships. Yamamoto kept his fleet of four carriers, including Shokaku, 199 planes, 6 battleships, 10 cruisers, and 22 destroyers of the Japanese Combined Fleet northwest of the Solomon Islands waiting for a chance to approach and destroy the American fleet at Guadalcanal. The American fleet was comprised of 2 fleet carriers, 136 planes, 1 battleship, 6 cruisers, and 14 destroyers.
By 5:00am on the 26th both carrier groups were within 200nmi of each other. The US Navy using their advanced radar and spotted the Japanese planes incoming. However, poor search plane reports on both sides seemed to aid the Americans more in this situation. Eleven American SBD dive-bombers attacked Shokaku at 09:27am, hitting her with three to six bombs and damaging her flight deck. This also caused serious damage to the hanger deck below and even decks deeper within the bowels of the ship. Kondo's Advance force and the Vanguard force warships altogether headed directly towards the last reported position of the US carrier task force trying to overtake them. Zuiho was damaged severely enough that she could no longer recover any of her planes. The damaged Shokaku, with Admiral Nagumo onboard, retired from the battle area, leaving Rear Admiral Kakuji Kakuta in charge onboard the Zuikaku. Kakuta helmed the remainder of the carrier force that included the carrier Junyo. The American carrier USS Hornet was abandoned when Kakuta's ships found her adrift. She was checked to see if salvage was possible but was later torpedoed by IJN destroyers when it was decided Hornet was a total loss.
The battle losses and damage for the American fleet were one carrier (the USS Hornet) sunk plus one destroyer, 26 air crew lost, 81 aircraft destroyed, one carrier damaged along with two destroyers and 266 men KIA. Again, the battle served as a tactical Japanese victory in terms of no ships lost but Japan did lose another 99 aircraft and, most importantly, between 400 and 500 men KIA. The losses for the Japanese Navy were 148 air crewmen including five squadron leaders and eighteen section leaders. Japan could not withstand such losses of trained men for the duration of their war. Japanese torpedo bomber aircrews lost 49% of their total number on the four carriers with 39% of the dive bomber crews and 20% of the fighter pilots.
These losses of Japanese aircrew at Santa Cruz combined with previous carrier battle losses at Coral Sea of 90 men, at Midway losing 110 crew and the Eastern Solomons totaling 61 killed was a loss of 409 total of the 765 elite Japanese carrier aviators who had participated in the Attack on Pearl Harbor. After the Battle of Santa Cruz, the undamaged Zuikaku and Hiyo were required to return to Japan because they did not have enough pilots and mechanics to man their air groups. Upon return to Japan, Admiral Nagumo was relieved of command. The four carrier battles against the Americans decimated the IJN veteran carrier aircrews and such losses woudl play a critical role in the demise of the Empire by war's end, leading to the rise of the "kamikaze" suicide pilot. The Japanese military had a mindset that its Army and Navy were invincible so reserve planning was an inadequate gesture. The Americans believed otherwise and would ultimately come up the victors in this foray.
Battle for Attu, Alaska
What is generally referred to as the "Forgotten Battle" of World War 2 became the Battle for Attu in the Aleutian Island chains of Alaska. This part of the world was a cold, dreary place and crews stationed in such an environment had to contend with the worse that nature had to offer for both man and machine. Regardless, American crews made this place their home for a time, ensuring that the Aleutians remained a strategic position for the American military in the North Pacific. In May of 1943, Shokaku was assigned to attack allied positions across the Aleutian Islands but the invasion was quickly cancelled after the Allied victory at Attu killed approximately 4,350 Japanese and seven warships and nine transports were sunk.
Battle of the Philippine Sea
For the balance of 1943, Shokaku was stationed at Truk. In 1944, she was based in the Lingga Islands, just south of Singapore. Shokaku departed with the Mobile Fleet for Operation A-Go on June 15th, 1944. The operation was a counterattack against Allied forces in the Mariana Islands. The Battle of the Philippine Sea would become the largest carrier battle of the war. The American Fifth Fleet, TF-58, was composed 15 carriers with 956 aircraft, 7 battleships, 79 cruisers and destroyers plus 28 submarines. The Imperial Japanese Fleet sent 9 carriers with 450 carrier-based planes, 5 battleships and 43 cruisers and destroyers and 300 land-based planes. The Teutonic battle between the American and Japanese navies was coming to pass. The Japanese had always wanted a clash of naval guns with the Americans but it had not happened up to this point - perhaps this would be the victory they sought.
On June 12th, 1944, US carrier planes attacked the Marianas. The IJN commander Admiral Toyoda received the news and was convinced that the US was preparing to invade. Toyoda had expected the next American target to be the Carolinas and the Japanese high command had only minimal forces in the Marianas to repulse such an attack. On June 13th, American battleships began bombardment operations for invading Saipan. Toyoda now had no choice and ordered a fleet counterattack. The Battle of the Philippine Sea, also called the "Battle for the Marianas" by the IJN, had begun. American submarines began to monitor the Japanese fleet on June 15th. The next day, Admiral Raymond Spruance, commander of the US 5th Fleet, surmised the IJN was moving towards the Marianas to counter the Saipan invasion force. By June 18th, Vice Admiral Marc Mitscher, aboard his flagship the USS Lexington, put his Task Force 58, the Fast Carrier Task Force, on battle alert to protect the amphibious forces near Saipan against the Japanese attack.
Shokaku and her sister carriers launched aircraft first, this around 5:00am on June 19th, 1944 along with Army aircraft including "Zeros" from Guam. The morning was starting all wrong for the Japanese aircraft when a large group of American Grumman F6F Hellcat fighters shot down 35 Japanese aircraft within view of ships of TF-58. Around 10:00am, radar on picket ships of TF-58 radioed 68 Japanese aircraft, 150 miles from the fleet. TF-58 launched all fighter aircraft and met the IJN planes at 70 miles out at 10:30am and, quickly, 25 Japanese planes were shot down. On their return trip to the IJN carriers, another 16 planes were downed with the loss of only one Hellcat - something was shaping up in the after-action reports of the American pilots, reporting average-to-poor flying by the Japanese. Attrition was beginning to show through.
At 11:07, a larger wave of 109 Japanese aircraft was detected by radar and several got thru the protective perimeter, attacking three TF-58 carriers. None scored a direct hit and 97 of the 109 aircraft were shot down. A third wave of 47 came in, losing seven aircraft while the balance diverted to Guam. The fourth wave was comprised of 49 aircraft but suffered eight losses while attacking carriers. Running low on fuel, the remaining 41 Japanese planes proceeded to Guam to refuel and were assaulted by 27 Hellcats. Thirty Japanese aircraft were downed with rest damaged. One of the Hellcat pilots was quoted as saying "Hell, this is like an old-time turkey shoot!". As the news of the action went through the American fleet, the one-sided air battle was therefore dubbed "The Great Marianas Turkey Shoot".
About 200 miles away from the American carriers of TF-58, three front-line Japanese carriers - the Taiho, Zuikaku, and Shokaku - steamed in formation, having already launched air strikes against the US carriers. The Zuikaku was in the lead with the Taiho on the port side and Shokaku on the starboard quarter of the arrowhead formation. Onboard the carriers, the men were still hopeful of the great deciding victory battle against the American Navy.
The submarine USS Albacore was trailing Admiral Ozawa's carrier flagship, the Taiho. The destroyer screen had not detected the sub, allowing her to move into firing position. Two "fish" (torpedoes) were fired with one hitting the carrier forward. The crew onboard Taiho initially felt the damage was not serious as smoke was almost nonexistent but, unknown to them, aviation gas fumes were seeping below decks and combustion would eventually cause her doom. About two hours later, the USS Cavalla had arrived on the southern flank of the Japanese fleet and sighted the Shokaku in the progress of landing aircraft. Taiho was barely trailing smoke in the distance, however the fuel vapors were increasing below deck.
Cavalla moved into position, watching the carrier screen closely. Her skipper, Lt. Comdr. Herman Kossler, calculated Shokaku's speed and course while watching a destroyer steam along her starboard side. He watched the destroyer for any indication that the vessel had spotted his submarines position but he saw none. Kossler slowly moved the periscope North West to observe the two cruisers steaming ahead of the carrier's port side. Kossler smiled thinking how lucky he was for a great shot. At a range of 1,200 yards the Cavalla fired a six-strong torpedo spread at Shokaku's starboard side. At the last moment, at 11:20am, the lookouts aboard Shokaku sighted torpedoes off the starboard bow - this too late for Captain Matsubara to react and evade the torpedoes even though he gave the order to do so. Three or four of the torpedoes plowed into the ship at about six to eight seconds apart. All the torpedo hits were destructive but, again, like the Taiho, the damage was not seen by the crew as fatal. All of the hits started amidships-to-forward. The hit under the island ripped the main AV gas line creating a fiery spray both on the flight deck and hanger deck. Some aircraft that had landed were covered with flaming gas and aircraft being fueled in the hangar began exploding. The explosion damaged the aircraft lifts and several fell from the flight deck with many men falling directly into the flames below.
Gas spewed on ammunition on the hoists began to explode, turning the hangar deck into a shipborne holocaust. Exploding bombs and aircraft fuel tanks added to the conflagration, killing men as they fought the fire. Reportedly, burning body parts could be seen laying about the deck. A torpedo blew a hole in the boiler rooms along the starboard side and they began taking water - flooding and fire were a sea vessels worst scenarios, requiring crew to be specially trained in their handling. Shokaku slowed and, by losing speed, she had to fall out of formation. She began to list (tilt) to starboard. There was little panic in the Shokaku's experienced crew for they had already saved their ship twice before. Orders came from the bridge to counter the flooding but the flooding was such that it forced the ship to list to port instead of coming back to centerline. The main problem was a slow steady trim to the bow. Soon after, Shokaku went dead in the water.
The fire in the hangar had not been extinguished and was, in fact, out of control. Many of the electric circuits had failed immediately following the torpedo hits. Ammunition was exploding and, without power, the forward pumps failed. The experienced damage control teams used all of the firefighting equipment available - from hand extinguishers to "bucket brigades" to help control the fires. The brave men faced extreme heat and flame with exploding bombs and torpedoes all about. Regardless of national position, it can be agreed by all readers that all onboard served their ship above and beyond their duty call. If power could be restored, there might be some hope to restart the pumps but this was not to be. Damage control had made some progress with the main fire concentrated forward and amidships but exploding ammunition mixed with leaking gas cancelled out their courageous efforts.
At 1:00pm, the intensity of the flames on Shokaku was becoming an inferno that was now visible on the flight deck, coming up from the hanger deck elevator wells. Her screening ships could now see two carriers burning. The bow continued to settle and Captain Matsubara knew all that could be done had been done by his crew. Orders were given to find all hands and many officers went below to ensure all would be given the abandon ship order. Soon, hundreds of men were gathered on the aft deck while a roll call was made. Some did not wait and jumped into the sea, joining many that had fallen off the ship during explosions. As the men waited on the aft deck for the order to go over the side, bombs continued to explode inside the ship. How these men could stand along the flight deck while the ship was breaking up around them we will never know. Suddenly, five massive explosions rocked the ship from below decks. The stern quickly lifted skyward as the weight of water flowed in forward into the Number 1 elevator. The men on the aft deck were surprised and knocked off their feet, sliding down the deck forward.
The men in the water could hear their crew mates scream as they tumbled down the flight deck to their deaths, falling into the flames coming out of the open Number 3 elevator, only to be engulfed below - a fate no crew should have to endure. Getting into the water was also no saving grace for the oil spilled during such an attack made it impossible to breath. The ship continued to go down by the head, now with the stern vertical to the water. Burning and exploding, she sank into the deep. The men in the water watched the mighty Shokaku and some sang the ships song with great sorrow as she disappeared at 2:12pm. Shokaku 's escorts picked up whatever men could be found as IJN destroyer's depth-charged the possible position of the USS Cavalla for the next three hours. The sub's crew counted 106 depth charges but Cavalla inevitably escaped. Of the Shokaku's compliment of 1,660 officers and men, 1,263 men went down with their ship, this made up of 887 officers and men as well as 376 men of Air Group 601.
The US Navy lost no ships and 123 planes were lost mostly during the ensuing night landings. 80 crews were picked up having been saved by American submarine picket boats. The IJN lost three carriers and two oilers with three carriers and three other warships damaged. The inexperienced Japanese pilots lost 433 carrier planes along with another 130 destroyed when their carriers sunk. An additional 200 land-based aircraft were shot down in battle.
The losses of these planes and pilots destroyed the IJN carrier force for good, they never to return to their former glory for the duration of the war.