This event has 3 ranks: easy (丙), medium (乙), hard (甲).
You can choose the difficulty in each map separately.
Different difficulties give different medals, equipment and materials when clearing the maps.
Ships rewards (U-511, Katori and Amagi) will appear regardless of the difficulty.
Difficulties probably affect drop rates, but ships still drop in any difficulty.
When the difficulty is changed, the boss's health bar will be reset.
Once the map is cleared (boss HP bar is depleted and killed), you CANNOT go back and change the difficulty.
There is no ship locking for this event.
The boss HP gauges does not regenerate over time in any map in any difficulty.
Support Expeditions are available. Expedition 141 Focuses on Support for Normal Nodes, Whereas Expedition 142 Focuses Support on Boss Nodes. The Expeditions DO REQUIRE that you have 2 DDs in your fleet. Do take note that their expeditions will end early after you finish one sortie, so try to make the most use out of them.
A fleet without DD/CL/CVL/Akitsumaru/Akashi will always end up at the dead end J
At least 2 DD/CL/CVL/Akitsumaru/Akashi OR 1 CV + 1 CVL(any combination) and not more than 1 CLT required to start with node A
2 BBVs will send you to the maelstrom node
1 CL, at least 3 DD, fast fleet, and and not more than two of (CL, CLT, CA (not CAV), BB, CV, empty slot) required to go from A to D, otherwise you go to F.
A fleet with at most 1 BB and at most 1 CV goes from F to G, otherwise it's H
LOS check from G/H to I
If you're having trouble getting to the boss, it's advisable to avoid starting at node B; fuel loss = higher chances to get hit
2 FBB 2 CV 1 CL 1 DD
3 FBB 2 CV 1 DD
1 CLT 2BB 1 CV 1 CVL 1 DD (A-F-H-I)
3 BB 2CV 1CVL (B-C-F-H-I)
1 DD 1 CL 2CV 2FBB
2 BB 1 CA 2CVL 1CV
2CA(V) 2CL 2CV (Light Fleet Ver.)
2FBB, 2CV, 2CVL
2FBB, 1CAV, 1CA, 2CVL
2FBB, 1CV, 1CVL, 1CA, 1CL
2FBB, 2CV, 1CVL, 1DD
2FBB, 2CV, 1CAV, 1DD
1FBB, 1CV, 1CVL, 1CAV, 1CA, 1DD (A-F-G-I)
CLT can be taken, without 2CVL bound to going to maelstrom node
Akizuki (Kai), Fubuki (Kai Ni), Hatsushimo (Kai Ni), Ushio (Kai Ni) or Shigure (Kai Ni) for doing AA cut-in (especially in the boss node) due to their high AA stats, reduces chances of damage from Nu-class flagship and Wo-class flagship
The boss BGM is 『吹雪』, the ending theme of the anime. However, the song will start on a different stanza than the one used in E-1.
Having a CLT in second fleet will send you E to F.
4 FBB + 1 CV + Akitsumaru (1st fleet) and 1 CL + 1 CLT + 4 DD (2nd fleet) will go either A->B->F->H->K or C->E->F->H->K (random). 4 battles total either way.
2 FBB + 2 CAV + 2 CVL (1st fleet) and 1 CL + 1 CA + 4 DD (2nd fleet) will go C->E->H->K. This is only 3 battles total and is probably the shortest route to boss. Though there is a fuel maelstrom at E.
[Quick Response] - 2 FBB + 1 CAV + 3 CV (1st fleet) and 1 CL + 1 CA + 4 DD (2nd fleet) works pretty well if you have the ships supporting this composition. Goes A->B->F->H->K or C->E->F->H->K (random). Usually using top right formation (survive) until the boss node, then switch to bottom right (battle).
2BB+1BBV+2CAV+CV (1st) 4DD+1CL+1CA (2nd) C->E->H->K Hard Mode
[Quick Response] - 1 BB 1 FBB 3 CV 1 CA (1st fleet) and 1 CL 1 CLT 3 DD 1 FBB (2nd fleet) will go A->B->F->H->K or C->E->F->H->K. There is a fuel maelstrom at node E.
[Quick Response] - 2 FBB 2 CAV 2CV (1st fleet) and 1 CL 1 CAV 4 DD (2nd fleet) will go C->E->H->K.