Question: When were two Japense carriers sighted, indicating an air strike en route?
About the article "Battle of Midway", section "Initial air attacks".

Candidate passages:
The 1st Mobile Fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day.
Upon reaching Guimares, the fleet refueled and sortied into the Philippine Sea where they spotted Task Force 58 on 18 June.
The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning.
He had deployed his forces in a "T"- shaped formation with the 3rd Carrier Division at the end of the stem, ahead of the 1st and 2nd Carrier Divisions that formed the crossbar of the "T".
"Zuihō" and her consorts were intended to draw the attentions of the Americans while the other carriers conducted their air strikes without disruption.
The first wave of search aircraft spotted one group of four carriers from Task Force 58 at 0734 and the Japanese carriers launched their aircraft an hour later.
This consisted of 43 Zero fighter-bombers and 7 B6Ns, escorted by 14 A6M5 fighters; the carriers retained only three fighters, two fighter-bombers, two B6Ns and two B5Ns for self-defense and later searches.
While the air strike was still forming up, the second wave of searchers located Task Force 58's battleships and the air strike was diverted to attack them.
The Americans detected the incoming Japanese aircraft and had a total of 199 Grumman F6F Hellcat fighters in the air by the time the Japanese aircraft were in range of the American ships.
The defending fighters decimated the Japanese aircraft and only 21 survived, doing little damage to the American ships.
Some of the surviving Japanese aircraft landed at Guam while others, including the five surviving B6Ns, returned to their carriers where they claimed one carrier definitely damaged and another probably hit.
At dusk, the Japanese turned away to the northwest to regroup and to refuel and the Americans turned west to close the distance.
Both sides launched aircraft the next day to locate each other; "Zuihō" launched three aircraft at 1200 to search east of the fleet, but they did not discover the Americans.
The Americans discovered the retiring Japanese fleet during the afternoon and Vice Admiral Marc Mitscher ordered an air strike launched.
While they sank one Japanese carrier and damaged two others, "Zuihō" was not attacked and successfully disengaged that evening.
By the end of the battle, Air Group 653 was reduced to two Zero fighters, three Zero fighter-bombers and six torpedo bombers.
After reaching Japan on 1 July, the ship remained in Japanese waters until October, training replacements for her air group. 
The 1st Mobile Fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day.
Upon reaching Guimares, the fleet refuelled and sortied into the Philippine Sea where they spotted Task Force 58 on 18 June.
The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning.
He had deployed his forces in a "T"- shaped formation with the 3rd Carrier Division at the end of the stem, ahead of the 1st and 2nd Carrier Divisions that formed the crossbar of the "T".
"Zuihō" and her consorts were intended to draw the attentions of the Americans while the other carriers conducted their air strikes without disruption.
Sixteen Aichi E13A floatplanes were launched by the heavy cruisers accompanying the carriers at 0430 to search for the Americans; the three carriers launched a follow up wave of 13 B5Ns at 0520.
The first wave spotted one group of four carriers from Task Force 58 at 0734 and the Japanese carriers launched their aircraft an hour later.
This consisted of 43 Zero fighter-bombers and 7 B6Ns, escorted by 14 A6M5 fighters; the carriers retained only three fighters, two fighter-bombers, two B6Ns and two B5Ns for self-defense and later searches.
While the air strike was still forming up, the second wave of searchers located Task Force 58's battleships and the air strike was diverted to attack them.
The Americans detected the incoming Japanese aircraft at 0959 and had a total of 199 Grumman F6F Hellcat fighters in the air by the time the Japanese aircraft were in range of the American ships.
The defending fighters decimated the Japanese aircraft and only 21 survived.
The only damage inflicted was from one A6M2 that hit the battleship in her superstructure with a single bomb that wounded 50 crewmen, but did little other damage.
Only three Hellcats were lost in the affair, one to a B6N, although the Japanese claimed four victories.
Some of the surviving Japanese aircraft landed at Guam while others, including the five surviving B6Ns, returned to their carriers where they claimed one carrier definitely damaged and another probably hit.
At dusk, the Japanese turned away to the northwest to regroup and to refuel and the Americans turned west to close the distance.
Both sides launched aircraft the next day to locate each other; "Zuihō" launched three aircraft at 1200 to search east of the fleet, but they did not discover the Americans.
The Americans discovered the retiring Japanese fleet during the afternoon and Vice Admiral Marc Mitscher ordered an air strike launched.
While they sank the Japanese carrier "Hiyo" and damaged two others, "Zuihō" was not attacked and successfully disengaged that evening.
By the end of the battle, Air Group 653 was reduced to two Zero fighters, three Zero fighter-bombers and six torpedo bombers.
After reaching Japan on 1 July, the ship remained in Japanese waters until October, training replacements for her air group. 
The Japanese fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day.
Upon reaching Guimares, the fleet refuelled and sortied into the Philippine Sea where they spotted Task Force 58 on 18 June.
The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning.
At this time, Air Group 652 consisted 81 Zeros, 27 D3As, 9 Yokosuka D4Y "Judy" dive bombers and 18 Nakajima B6N "Jill" torpedo bombers, roughly evenly divided among the three ships.
The three carriers began launching their first air strike of 26 bomb-carrying A6M2 Zeros, 16 A6M5 Zeros to escort the other aircraft and seven B6Ns at about 09:30.
Most of these aircraft were misdirected and failed to find any American ships, although a dozen persisted in their search and found one of the American task groups.
Five bomb-carrying Zeros, a B6N and an escort Zero were shot down by the defending fighters and no damage was inflicted on any American ship.
A second air strike of 27 D3As, nine D4Ys, two B6Ns and 26 escorting Zeros was launched around 11:00, accompanied by at least 18 A6Ms and B6Ns from and .
They had also been given an erroneous spot report and could not find any American ships.
The 652nd aircraft headed for airfield at Rota and Guam to refuel while those from the other two carriers headed back to them.
Six D4Ys and two Zeros bound for Rota spotted the carriers and en route and failed to inflict any damage on the American ships while losing five D4Ys to anti-aircraft fire.
Radar had spotted those aircraft headed for Guam and they were intercepted by 41 Grumman F6F Hellcats.
Only one A6M5, one D4Y and seven D3As of the 49 Japanese aircraft survived the encounter and landed.
At dusk, the Japanese turned away to the northwest to regroup and to refuel and the Americans turned west to close the distance.
They discovered the retiring Japanese fleet during the afternoon of the following day and Vice Admiral Marc Mitscher ordered an air strike launched.
"Hiyō" was struck by two bombs, one of which detonated above the bridge and killed or wounded virtually everyone there.
More seriously, the ship was struck by one torpedo dropped by a Grumman TBF Avenger from .
This knocked out the starboard engine room and started fires, but "Hiyō" was able to continue, albeit a slower speed.
Two hours later, a large explosion occurred when leaking gasoline vapor ignited and it knocked out all power on the ship.
The fires raged out of control and "Hiyō" sank stern first shortly afterwards at .
Roughly 1,000 men were rescued by her escorting destroyers, but 247 officers and enlisted men died aboard the carrier. 
On 9 May, TF 17 altered course to the east and proceeded out of the Coral Sea via a route south of New Caledonia.
Nimitz ordered Fletcher to return "Yorktown" to Pearl Harbor as soon as possible after refueling at Tongatabu.
During the day, U.S. Army bombers attacked Deboyne and "Kamikawa Maru", inflicting unknown damage.
In the meantime, having heard nothing from Fletcher, Crace deduced that TF17 had departed the area.
At 01:00 on 10 May, hearing no further reports of Japanese ships advancing towards Port Moresby, Crace turned towards Australia and arrived at Cid Harbor, south of Townsville, on 11 May.
At 22:00 on 8 May, Yamamoto ordered Inoue to turn his forces around, destroy the remaining Allied warships, and complete the invasion of Port Moresby.
Inoue did not cancel the recall of the invasion convoy, but ordered Takagi and Gotō to pursue the remaining Allied warship forces in the Coral Sea.
Critically low on fuel, Takagi's warships spent most of 9 May refueling from the fleet oiler "Tōhō Maru".
Late in the evening of 9 May, Takagi and Gotō headed southeast, then southwest into the Coral Sea.
Seaplanes from Deboyne assisted Takagi in searching for TF 17 on the morning of 10 May.
Fletcher and Crace, however, were already well on their way out of the area.
At 13:00 on 10 May, Takagi concluded that the enemy was gone and decided to turn back towards Rabaul.
Yamamoto concurred with Takagi's decision and ordered "Zuikaku" to return to Japan to replenish her air groups.
At the same time, "Kamikawa Maru" packed up and departed Deboyne.
At noon on 11 May, a U.S. Navy PBY on patrol from Nouméa sighted the drifting "Neosho" ().
The U.S. destroyer responded and rescued 109 "Neosho" and 14 "Sims" survivors later that day, then scuttled the tanker with torpedoes.
On 10 May, the "RY" operation commenced.
After the operation's flagship, minelayer , was sunk by the American submarine on 12 May (), the landings were postponed to 17 May.
In the meantime, Halsey's TF 16 reached the South Pacific near Efate and, on 13 May, headed north to contest the Japanese approach to Nauru and Ocean Island.
On 14 May, Nimitz, having obtained intelligence concerning the Combined Fleet's upcoming operation against Midway, ordered Halsey to make sure that Japanese scout aircraft sighted his ships the next day, after which he was to return to Pearl Harbor immediately.
At 10:15 on 15 May, a Kawanishi reconnaissance aircraft from Tulagi sighted TF 16 east of the Solomons.
Halsey's feint worked.
Fearing a carrier air attack on his exposed invasion forces, Inoue immediately canceled "RY" and ordered his ships back to Rabaul and Truk.
On 19 May, TF 16 – which returned to the Efate area to refuel – turned towards Pearl Harbor and arrived there on 26 May.
"Yorktown" reached Pearl the following day.
"Shōkaku" reached Kure, Japan, on 17 May, almost capsizing en route during a storm due to her battle damage.
"Zuikaku" arrived at Kure on 21 May, having made a brief stop at Truk on 15 May.
Acting on signals intelligence, the U.S. placed eight submarines along the projected route of the carriers' return paths to Japan, but the submarines were not able to make any attacks.
Japan's Naval General Staff estimated that it would take two to three months to repair "Shōkaku" and replenish the carriers' air groups.
Thus, both carriers would be unable to participate in Yamamoto's upcoming Midway operation.
The two carriers rejoined the Combined Fleet on 14 July and were key participants in subsequent carrier battles against U.S. forces.
The five "I"-class submarines supporting the "MO" operation were retasked to support an attack on Sydney Harbour three weeks later as part of a campaign to disrupt Allied supply lines.
"En route" to Truk, however, "I-28" was torpedoed on 17 May by the U.S. submarine and sunk with all hands. 
The Japanese fleet was en route to Guimares Island in the central Philippines on 13 June, where they intended to practice carrier operations in an area better protected from submarines, when Vice Admiral Jisaburō Ozawa learned of the American attack on the Mariana Islands the previous day.
Upon reaching Guimares, the fleet refuelled and sortied into the Philippine Sea where they spotted Task Force 58 on 18 June.
The Americans failed to locate Ozawa's ships that day and the Japanese turned south to maintain a constant distance between them and the American carriers as Ozawa had decided on launching his air strikes early the following morning.
At this time, Air Group 652 consisted 81 Zeros, 27 D3As, 9 Yokosuka D4Y "Judy" dive bombers and 18 Nakajima B6N "Jill" torpedo bombers, roughly evenly divided among the three ships.
The three carriers began launching their first air strike of 26 bomb-carrying A6M2 Zeros, 16 A6M5 Zeros to escort the other aircraft and seven B6Ns at about 09:30.
Most of these aircraft were misdirected and failed to find any American ships, although a dozen persisted in their search and found one of the American task groups.
Five bomb-carrying Zeros, a B6N and an escort Zero were shot down by the defending fighters and no damage was inflicted on any American ship.
A second air strike of 27 D3As, nine D4Ys, two B6Ns and 26 escorting Zeros was launched around 11:00, accompanied by at least 18 A6Ms and B6Ns from "Shōkaku" and .
They had also been given an erroneous spot report and could not find any American ships.
The 652nd aircraft headed for airfield at Rota and Guam to refuel while those from the other two carriers headed back to them.
Six D4Ys and two Zeros bound for Rota spotted the carriers and en route and failed to inflict any damage on the American ships while losing five D4Ys to anti-aircraft fire.
Radar had spotted those aircraft headed for Guam and they were intercepted by 41 Grumman F6F Hellcats.
Only one A6M5, one D4Y and seven D3As of the 49 Japanese aircraft survived the encounter and landed.
By the end of the day, Air Group 652 had been reduced to only 38 Zeros, evenly split between bomb-carrying A6M2s and escort A6M5s, and eight B6Ns.
At dusk, the Japanese turned away to the northwest to regroup and to refuel and the Americans turned west to close the distance.
They discovered the retiring Japanese fleet during the afternoon of the following day and Vice Admiral Marc Mitscher ordered an air strike launched.
They discovered the ships of the Second Carrier Division and hit "Jun'yō" with two bombs near her island.
The ship was not badly damaged, but the damage did stop flight operations.
Air Group 652 claimed two Grumman F6F Hellcat fighters and nine Grumman TBF Avenger torpedo bombers shot down, but lost 11 aircraft, plus another three that had to ditch.
By the end of the battle, the air group only consisted of 11 A6M5s, 5 A6M2s and 1 B6N and it was disbanded on 10 July.
Most of its remaining personnel were assigned to Air Group 653.
After repairs at Kure, she remained in the Inland Sea without aircraft until 27 October when she was tasked to transport material to Borneo.
On 3 November, while en route, she was attacked by the submarine near Makung, but her escorting destroyer, , deliberately sacrificed herself by intercepting the torpedoes and sank with no survivors.
On her return voyage, the ship was unsuccessfully attacked by the submarines and .
On 25 November, she sailed for Manila via Makung to rendezvous with the battleship and the destroyers "Suzutsuki", "Fuyutsuki", and "Maki".
Having loaded 200 survivors of the battleship , "Jun'yō" was attacked by the submarines , and early in the morning of 9 December 1944.
She was hit by three torpedoes that flooded several compartments and killed 19 men.
These give her a 10°–12° list to starboard, but she was able to proceed on one engine.
She reached Sasebo the following day and began repairs on 18 December.
The repairs were abandoned in March 1945 for lack of materials and the ship was moved from the dock to Ebisu Bay, Sasebo on 1 April.
Efforts to camouflage the ship began on 23 April and she was reclassified as a guard ship on 20 June.
"Jun'yō"s armament was ordered removed on 5 August and the ship was surrendered to the Allies on 2 September.
An American technical team evaluated the ship's condition on 8 October and deemed her a constructive total loss.
"Jun'yō" was stricken from the Navy List on 30 November and scrapped between 1 June 1946 and 1 August 1947 by the Sasebo Ship Company.