Events/Mechanics

Several new gameplay mechanics are implemented in each new Event, some of which are Event-exclusive. These mechanics may change gameplay drastically, and the event-exclusive ones are described here.

Combined Fleet
See main article: Combined Fleet

The Combined Fleet system was first introduced in the Battle of Midway during the Summer Event of 2014, and has been present since as an event-exclusive mechanic. In a Combined Fleet, you'll have to organize and sortie the first two fleets together, allowing for up to 12 ships (instead of the usual 6) to be sortied out at once. Combined fleets can only be sortied to the maps that require it. See the dedicated page for more info.

Ship Locking
Introduced in the Summer 2014 Event, this mechanic locks ships that were sortied out to specific event maps, and will be unable to participate in other ship-locked maps. A ship girl will receive her map lock as soon as she sorties to a ship-locking event map. Afterwards, it's impossible to remove the lock till the end of the event. Remodeling or marriage will NOT remove the shiplock. However, this locking only applies to that ship's specific ID, so any other ship with same name will not have the same lock. Support expeditions will not receive locks.

Here's an example using the Summer 2015 Event:
 * Sending Shimakaze to E-1 and/or E-2 would lock her to E-1 and E-2 and thus unable to participate in the subsequent maps sans the final map.
 * Sending Nagato to E-3 would lock her to E-3 and E-6 and thus unable to be sent to Map E-2, E-4 or E-5.
 * Sending Kongou to E-4 would lock her to E-4 and cannot be sortied out to any other map sans the final map.
 * Sending Yamato to E-6 would lock her to E-6, but she can also participate in E-3 which has the same tag.
 * Sending Kitakami to E-5 would lock her to E-5 only, effectively locking her out from the rest of the other event maps.
 * Sending Akitsumaru to E-7 won't lock her, and she is free to sortie to any of the earlier event maps until she is actually sortied to any of them, where their respective ship locks would then be applied.
 * All the aforementioned ships are able to sortie to E-7 on Hei-rank (Easy). However, Kitakami would be unable to sortie there at higher difficulties as E-7 does NOT allow locks from E-5.

This mechanic varies for each and every event, so make sure you check the specific Event pages themselves for more info on how the maps are locked. This is also a reason to keep multiple ships per ship-type prepared. If you lack in certain ship-types, you may not be able to fulfill branching routes on later maps, or may be forced to use an un-optimal composition.

Support expeditions do not check for ship locks, with the exception of the Summer 2014 Event (AL/MI).

Difficulty Selection
Starting from the Winter 2015 Event, players can choose the difficulty of each event map from three difficulties: Easy (丙), Medium (乙), and Hard (甲). (Replacing the old dynamic difficulty system)

Differences= Different difficulties yield different rewards, with harder tiers giving more items, or better versions of the same base item type. Ship rewards are always given, regardless of difficulty. Ship drops differ, with some ships available only to medium/hard, and certain drop rates are increased on higher difficulties. Enemy compositions differ depending on difficulty, especially bosses and their escorts. Whether if it's more efficient to farm a lower drop rate on Easy, or with a higher drop rate on Hard/Medium, depends on the differences in drop rates and the preparedness of the player's fleet.

Ship locks, if applicable, will be placed regardless of difficulty, but will only be enforced on Medium and Hard difficulties.

Clearing the last map of the Event on Hard (甲) mode will reward a First Class Medal. The First Class Medal can still be obtained even if any of the earlier maps were done on an easier difficulty, so long as the last map is cleared on Hard. Clearing the prior map on Easy (丙) mode will lock out Hard (甲) mode for the last map, so pay attention if you wish to obtain the First Class Medal.

Note that the original Japanese characters for the three difficulty tiers (which literally mean A/B/C) do not actually describe the difficulty of the mode. Instead, the difficulty is shown by the number of sakura petals directly below, where more petals indicate a higher difficulty. They're translated as such for the purpose of simplicity.


 * -|Requirements and Constraints=

Requirements

 * Easy difficulty is always unlocked
 * Medium is unlocked at HQ level 35
 * Hard is unlocked at HQ level 80

Constraints

 * Players may not change the difficulty after clearing the map (emptying the boss gauge).
 * Players may change the difficulty anytime before clearing the map, but the boss gauge will be fully restored upon doing so.
 * If it is a Transport Drop-off Map (see below) that requires you to sink the Boss HP bar after and the Transport (TP) Bar is already cleared player must clear the the TP Bar again if they change difficulty as it will reset everything (both TP and HP bars).
 * Players may not select Hard difficulty if the previous map was cleared on Easy . It's possible to jump to and from other difficulties otherwise.

Starting from the Spring 2015 Event, players on Easy mode would not have shiplock restrictions, allowing the the players to send shiplocked girls to maps that do not normally allow it. For example : If you used Ooi in E-4 Hard mode, you can use her in E-5 Easy mode, since easy mode ignores the ship lock. But, if you used Mogami in E-2 on Easy, you cannot use her in E-4 Medium/Hard modes.
 * -|Easy Mode Ship Tags=

Starting from the Summer 2015 Event, the required amount of boss kills required to clear a map varies depending on an Admiral's HQ Level. The higher the HQ Level is, the more kills it requires to complete a map.
 * -|HP Bar Scaling=

The following is an example from Winter 2016 event:

For example, to complete E-1 in Easy difficulty, a HQ105 Admiral would require 5 kills, while a HQ30 Admiral would require only 3.

However, it is still unknown whether there are more threshold levels aside from the ones that already exist in the table.

Map-specific Mechanics
Transport Load-Off=


 * The Fall 2015 Event E-5 boss, Destroyer Water Demon could be debilitated by sinking at least 30 PT Imp Packs during the TP-Bar Stage, or 15 PT Imp Pack during Boss HP Bar Stage. While the debilitation was in effect, the Destroyer Water Demon would lose her helmet.

The boss debilitation mechanism effect lasts until 05:00 hrs JST on Fall 2015 Event, except for the last day of the event.

Content merged into Land-Base Aerial Support
 * -|Land-Base Aerial Support=

LoS Check
Starting from the Spring 2014 Event event, LoS -based checks were implemented. Read the Line of Sight article for detail.

Node specific details
Aerial Battle= These nodes consist of two Aerial Combat phases, but they do not have any other regular combat phases (shelling/torpedo).

In combined fleet maps, as the 2nd fleet doesn't send out planes during aerial combat phases, no damage to the enemy fleet will be dealt by them, thus the 2nd fleet flagship will always get MVP in these nodes.


 * -|Air Raid Battle=

Also known as Manual Node Selection

Introduced in Spring 2015 Event, certain nodes allow you click on a node to specify which route you want to take. You may only choose nodes that are connected directly to the manual nodes.

Starting from Winter 2016 Event, maps with multiple branching options were introduced. These maps may have multiple starting or/and ending nodes. The starting node depends on the ships, or combined fleet type that was used to sortie on the map.
 * -|Multiple Branching=

As shown in the image, there were multiple start and end nodes in 2016 Winter event E-3. The first part was to deplete TP gauge, using a Transport Escort Fleet which started at node A and ends at node S. After which, players had the option of using either a Surface Task Force (Starts at node J) or Carrier Task Force (Starts at node E or F) to make their way to the final boss (node T).