As per Shattered Sword, (ie, Nagumo Report), Akagi quickly settled on a course of 300 degrees at 1015 in direct response to spotting TB-3 at 45,000 meters to the southeast. So no, it wasn't just Hiryu that reacted. Akagi did so as well, (she will have considered them a threat to Akagi too). Kaga was under torpedo attack at 1015 - she was probably careening all over the place. Soryu will presumably have conformed to the movements of the flagship, Hiryu. So Soryu would swing around to course 300 degrees and run northwest at about 30kt, because Akagi and Hiryu were doing so and Soryu is keeping station. Here's the Nagumo Report where the movements of Akagi are detailed,paulrward wrote:Hello Mr. Glenn239 ;
I must not have been clear. When VT-3 attacked, only one carrier ran straight to the northwest to evade it, and that was the Hiryu. This is what put her so far to the north at the end of the bombing attacks.
The other three carriers, Akagi, Kaga, and Soryu, were making tight, circling turns to evade the dive bombers, VB-6 and VS-6 which attacked Akagi and Kaga, and VB-3 which attacked Soryu. This is what led to the seperation of Hiryu from the other carriers: She was using a different defense doctrine in order to deal with a different type of attack.
http://www.ibiblio.org/hyperwar/Japan/I ... ay/Nagumo/
0711 Akagi swings around to place the starboard group of torpedo planes to her stern.
0714 Akagi settles on course 300 degrees.
0715 Akagi sights enemy torpedo plane group of 12 planes in position bearing 170 degrees to port, distance 45,000 meters.
0720 Akagi reports sighting bomber bearing 30 degrees directly over the Kaga and goes into a maximum turn.
0724 Noting that the two torpedo plane groups to starboard of the Akagi were preparing to launch their torpedoes, she goes into evasive action. Then, seeing that she was about to be dive bombed, she makes maximum reverse turn.
The starboard group is TB-3, so at 0711 (1011) Akagi is travelling approximately into the wind after recovering CAP at 1010. She swings to the northwest away from TB-3, settling onto a course of 300 degrees until she spots bombers over Kaga and starts to evade. At 0724 TB-3 is now close - close enough to Akagi that it is thought they are in attack range - and she evades them, and then sees the dive bombers.
Akagi and Soryu would not react to the dive bombers - that is, going into high speed circles - until these were spotted overhead. So, for Akagi, she's running in parallel with Hiryu to the northwest from 1015 to 1020. For Soryu, she's probably doing so for even longer, from 1015 to 1028. (Notice the Soryu's sinking position is northwest of Akagi's even though Akagi after being bombed moved northeast while Soryu quickly came to a stop and never moved again under her own power. Akagi peels off into evasive circles at 1020, while Soryu remains on 300 degrees with Hiryu at about 30kt for maybe seven or eight more minutes, until the dive bombers are spotted overhead).
To my mind, the question is not the location of Hiryu. It's the location of the Soryu.