Combat

For detailed explanations on specific mechanics, see their respective pages:

Combat Stages

For most combat engagements, the battle will begin in day combat and follow the following set of stages. Several stages will not occur unless certain conditions are met.

Combined Fleet uses a modified combat order.
For Air Battle Only nodes (1-6 and certain event map nodes; may be a single-fleet or Combined Fleet), there is no Opening Torpedo Salvo, and Day Combat is completely replaced by a second round of Aerial Combat.

Thus ships that cannot participate in Aerial Combat cannot attack. They can still perform Anti-Air Defense, as usual.

Stage	Notes
Formation Selection	With 4 or more ships in a fleet, a fleet formation must be selected before combat. The selected formation affects ship damage, hit rate, and defense. This step is skipped if you have 3 or fewer ships.
Detection	Requires planes or high detection stat (usually from RADAR). Success increases accuracy and evasion. Failure prevents participation of allied planes in the aerial combat phase (and will result in your Air Superiority value treated as 0). If no message is shown, it is treated as a failure.
Aerial Combat	Participants: CVLs and CVs equipped with fighter or bomber planes; BBVs, CAVs, AVs, and SSVs equipped with seaplane bombers; some enemy-specific ship classes If a side achieves Air Superiority or Supremacy in this stage, that side can use Artillery Spotting. All ships capable of launching attack or bomber planes will launch them in this stage (unless Detection is failed), regardless of current HP status. This step is skipped if there is no eligible participant.
Opening Stages	Expedition Supporting Fire Supporting Fire from Sortie Support Expeditions. This has an aspect of randomness and may not trigger. Opening Torpedo Salvo Participants: SS over level 10, ships equipped with Type A Ko-hyoteki (CLTs, Chitose, Chiyoda, Abukuma Kai Ni, SS) and enemy Battleship Re-Class Elite. All participants fire their torpedoes simultaneously. Unlike Closing Torpedo Salvo, a ship can launch a torpedo in this stage even when current HP is less than or equal to 50% of Max HP. Engagement Form The orientation of the allied and enemy fleets is displayed. The engagement form affects both fleets equally.
Day Combat	Shelling, 1st Round (Range Order) Participants: All ships except SS, CVLs and CVs not carrying any bombers, and basic Transport Ship Wa-Class. Firing order alternates between allied and enemy sides, starting with allied. Ships with longer range have priority. Ships on the same side tied in range will break ties randomly and assigned order within that side. The firing order is set as Allied Order #1 → Enemy Order #1 → Allied Order #2 → … The firing order is set at the start of the round; ships sunk or incapacitated before their turn is simply removed from the firing order. Shelling, 2nd Round (Lineup Order) Participants: All ships except SS, CVLs and CVs not carrying any bombers, and basic Transport Ship Wa-Class. Firing order is set at start of this round by alternating ships on each side that are normally capable of attacking during shelling rounds. Ships higher in lineup have priority. Only ships qualifying as Participant will be put in the lineup. For example, allied flagship is a CVL that is not carrying a bomber; 2nd round shelling would begin with the allied ship in the 2nd slot in the lineup (if it's capable of attacking). The firing order is set as Allied Lineup #1 → Enemy Lineup #1 → Allied Lineup #2 → … The firing order is set at the start of the round; ships sunk or incapacitated before their turn is simply removed from the firing order. Only occurs when either side has a BB, BBV, or the enemy has one of the special ship classes (鬼 Oni/Ogress, 姫 Hime/Princess) which acts like a BB/BBV: Destroyer Princess (駆逐棲姫, Destroyer Princess^?) does not, while Battleship Princess (戦艦棲姫, Battleship Princess^?) does. The distinction between Bosses that do and those that do not trigger this phase is not always clear from their names. Closing Torpedo Salvo Participants: DDs, CLs, CLTs, CAs, CAVs, Chitose, Chiyoda, SS, Bismarck drei, Battleship Re-Class, some enemy-specific ship classes; Requires current HP > 50% of Max HP and Base Torpedo Value > 0 Like the opening torpedo salvo, all participants attack simultaneously. Note that certain ships (Ooyodo, Maruyu, base Chitose, base Chiyoda) have initial innate torpedo value of 0; without modernization they cannot participate in closing torpedo salvo. Chitose and Chiyoda cannot increase their torpedo stat without remodeling. However, they can launch torpedoes during Opening Torpedo Salvo if equipped with Type A Ko-hyoteki.
Night Combat	Participants: All ships except CVLs, CVs, and basic Transport Ship Wa-Class. Enemy Standard Carrier Wo-Class and Light Carrier Nu-Class of flagship level or higher can attack at night. Requires current HP > 25% of Max HP The first slot allied ship attacks, then the first slot enemy ship attacks, and so on. If a ship is sunk or critically damaged, the game will skip its turn. The order differs from 2nd Shelling Round in that it does not "skip" ships already sunk prior to the start of the round.

For certain nodes and events, combat begins in the Night Combat stage, then proceeds to Day combat if certain conditions are met.

Formation Selection

With 4 or more ships in a fleet, a fleet formation must be selected before combat. The selected formation affects ship damage and hit rate.

Combined fleet uses a different set of formations unless it is a night battle only node. Click here for details.

Formation Modifier

Formation	Surface Damage Modifier	Anti-sub Damage Modifier	Anti-air Modifier	Day Shelling Hit Rate	Day Torpedo Hit Rate	Night Battle Hit Rate^[1]	Flagship Protection Rate
Line Ahead 単縦陣 (Tanjuu-jin, 単縦陣^?)	100%	45%	100%	Medium	High	High	Low
Double Line 複縦陣 (Fukujuu-jin, 複縦陣^?)	80%	60%	120%	High^[2]	Medium	Medium	Medium
Diamond 輪形陣 (Rinkei-jin, 輪形陣^?)	70%	90%	160%	Medium	Very Low	Very Low	High
Echelon 梯形陣 (Teikei-jin, 梯形陣^?)	60%	75%	100%	Medium	Low	Low	Medium
Line Abreast 単横陣 (Tan'ou-jin, 単横陣^?)	60%	100%	100%	High	Very Low	Medium	Medium

The surface damage modifier applies to both shelling and torpedo attacks, but does not affect Aerial Combat or Anti-Submarine attacks.
Diamond Formation is only selectable as a formation with 5+ ships.
Flagship protection is the situation where a non-flagship ship protects the flagship from being damaged by receiving the attack instead.
Line Ahead has the highest offensive power for surface combat. It is the default choice for encounters after the 3rd battle node to preserve firepower because of the remaining ammo penalty.
Double Line is generally a good formation for heavy BB/CV fleets. There is a significant accuracy increase that benefits the typically lower accuracy carriers, while BB often still have enough firepower.
Line Abreast is the best formation for anti-sub purposes.
Echelon has not been tested extensively, but it is hypothesized to be a defensive formation for submarines.

Detection

Fleet LOS affects Detection rate.
Success increases fleet accuracy and evasion.
Failure prevents participation of allied planes in the aerial combat phase.

Aerial Combat

Split into a separate page due to its length.

Opening Stages

The Opening Stages of combat proceed in order with the Supporting Expedition effect, the Opening Torpedo salvo, then the display of the engagement form

In World 5 and Event Maps, the Sortie fleet can receive a salvo of Support fire from fleets deployed on Support Expeditions. The type of supporting fire depends on the composition of the expedition fleet.
The Opening Torpedo Salvo is fired by Submarines over level 10, ships with the Type A Ko-hyoteki (CLTs, AVs, SS) equipped, and the Enemy Battleship Re-Class.

Torpedoes are fired from all ships simultaneously, and accuracy is affected by the selected Formation type.
Ships capable of firing in this phase will launch torpedo even if suffering moderate / heavy damage (which prevents launching torpedo during Closing Torpedo phase).
Opening torpedoes will prioritize targeting ships that can be damaged by them. If no such target exists, the torpedo will launch but always miss.

The Opening stages finish with the display of the Engagement form and the formation of the two fleets.

Engagement Form Modifier

Form	Damage Modifier	Chance	Chance with Saiun
Parallel Engagement 同航戦 (Doukousen, 同航戦^?)	100%	45%	45%
Head-on Engagement 反航戦 (Hankousen, 反航戦^?)	80%	30%	About 40%
Crossing the T (Advantage) T字戦有利 (T Ji-sen Yuuri, T字戦有利^?)	120%	15%	15%
Crossing the T (Disadvantage) T字戦不利 (T Ji-sen Furi, T字戦不利^?)	60%	10%	<1%

All engagement forms affect both sides equally, including crossing the T (Advantage or Disadvantage).
Regular night battle and aerial combat are not affected by engagement forms. Nodes starting with Night Combat, however, do take engagement forms into consideration (despite it not being displayed).
Equipping a Saiun effectively makes what would have been Crossing the T (Disadvantage) become Head-on Engagement.
It is speculated that the Engagement form also impacts accuracy.

Day Combat

Day Combat consists of up to 3 phases: 1st Shelling, 2nd Shelling (if applicable), Closing Torpedo
During the first shelling stage, the order of fire is determined by the ship's range.

Ships are arranged in order from Very Long → Long → Medium → Short → Very Short range.
The shelling order alternates from allied ships to enemy ships if able. If two ships on the same side have the same range, the ship that attacks first from between them is chosen randomly.
Very Short range only exists for enemy (all variants of Light Carrier Nu-Class and Standard Carrier Wo-Class).
Some equipments can extend the range of a ship, but in no cases will a ship's range decrease due to equipment.

The second shelling phase (if applicable) has an initial firing order of all ships alive that are normally capable of attacking during shelling phase, alternating between sides.
Ships unable to attack at all in the shelling phase (e.g. all submarines, basic Transport Ship Wa-Class, any carrier carrying no bombers) are not put into the shelling order (during both phases). Ships normally able to attack but rendered unable to (e.g. damaged carriers carrying bombers) will be included in the shelling order but take no action.
CVLs and CVs must be in good or lightly damaged condition in order to participate in either shelling phases; Armored Aircraft Carriers (e.g. Taihou) may still attack while moderately damaged.
The Closing Torpedo salvo is fired by all SS(V), DD, CL(T), CA(V), AV, Bismarck drei, and the enemy Battleship Re-Class.

Torpedoes are fired from all ships simultaneously, and accuracy (and damage) is affected by the selected Formation type.
Ships must not be moderately or heavily damaged to participate.
If any ship capable of firing torpedo is alive, this phase will occur (and text shown for start of phase), but if there is no valid target, no torpedo will fire.

Night Combat

Night battle damage depends on both the Firepower and Torpedo stats for attack power. Consequently, DDs, CLs, CLTs and CAs have drastically increased strength at night.
Any vessel at night must not be heavily damaged (red) before attacking in order to participate in night battle.
Certain combination of weapon equipment (Main Guns, Secondary Guns, Torpedoes) will cause Cut-In or Double Attacks at night, greatly increasing accuracy and/or firepower

Auxiliary equipment (e.g RADAR, SONAR, Depth Charges, Searchlights, Turbines, Special ammunition, Pure AA Equipment, Torpedo Bulges, and Midget-subs) will not affect the combination.

If night combat nodes are anticipated, it can be very helpful to utilize specialized night battle equipment such as Star Shells and Searchlight. Type 98 Recon Seaplane (Night Scout) is also an option.
Damage against submarines is greatly reduced during regular Night Battles (to scratch damage).
Formation damage modifiers do not apply in Night Battle (always 100% for regular shelling).

Nodes begin with Night Battle and in Combined Fleet Night Battle, Formation anti-sub damage modifiers apply.

The Engagement Form is not explicitly shown in Night Battle nodes, but the modifier will apply.

The animation for ships equipped with 2 different torpedoes may be different but the damage output is still the same.

A Prototype FaT Type 95 Oxygen Torpedo Kai + 61cm Quint (Oxygen) Torpedo Mount will show a cut-in animation of FaT+Quint+Quint and if equipped the other way around, the cut-in animation will show Quint+FaT+FaT. However, both animation produces the same damage output.

Damage Calculations

Main Formula

Pre-Cap Attack Power = Base Attack Power + Night Spotting Bonus + WG42 (Wurfgerät 42) Bonus
Attack Power Before Cap = [Pre-Cap Attack Power × Pre-Cap Modifiers + Light Cruiser Fitted Gun Bonus]
Cap-Adjusted Attack Power =	Attack Power Before Cap, if it is less or equal to the Attack Power Cap
Cap-Adjusted Attack Power =	Attack Power Cap + √(Attack Power Before Cap - Attack Power Cap), if Attack Power Before Cap is over the Attack Power Cap
Effective Armor = Enemy Armor × 0.7 + Random(0 ~ Enemy Armor -1) × 0.6
Final Attack Power = [Cap-Adjusted Attack Power × Critical Modifier] × Post-Cap Modifiers
Damage = (Final Attack Power - Effective Armor) × Remaining Ammo Modifier
Notes: The game rounds off values at 2 places in the calculation: after pre-cap modifier and after the critical modifier. They are marked by square brackets in the above calculations. If Damage is less than 1, the attack deals scratch damage* instead, which is 6-14% of target's current HP, rounded down (can be 0).* This formula is under constant review and updated accordingly if there are any inconsistencies or mistakes. Night Spotting Bonus: +5 if Type 98 Recon Seaplane (Night Scout) actviates. WG42 (Wurfgerät 42) Bonus: +75 against installation enemies; multiple equipped WG42 does not increase this bonus. Will work alongside Type 3 Shell.

Base Attack Power

Type	Base Attack Power	Notes
Opening Air Strike	Modifier × (Bomber's Dive Bomb or Torpedo stat) × √(Number of Planes) + 25	Number of planes is post anti-bomber combat and fleet anti-air defense Modifier is 1.0 for dive bombers, either 0.8 or 1.5 (50% chance for either) for torpedo bombers Calculated per slot.
Shelling (Carriers)	{[Firepower + Torpedo + Effective Bonus (Shelling) + (Dive Bomb × 1.3)] × 1.5} + 55	This is also the formula for Land-Based Abyssal ships during shelling rounds. (Uses the standard Night Battle formula at night.)
Shelling (Others)	Firepower + Effective Bonus (Shelling) + 5
Torpedo	Torpedo + Effective Bonus (Torpedo) + 5	Applies to both Opening and Closing Torpedo Salvo. Closing torpedo salvo will not be performed if innate Torpedo is 0 even if the ship is of a class that normally can.
Anti-sub warfare	√(Base Ship ASW) × 2 + Equipment ASW × 1.5 + Effective Bonus (ASW) + Ship Class Constant	Ship Class Constant: 13 for DD/CL/CLT, 8 for CAV/BBV/AV/CVL/LHA ASW stat for recon planes and radars are not counted at all for ASW damage. Even if sonars, depth charges, and other equipments with +ASW values are equipped, if the ship's innate ASW is 0 and no seaplane bomber, autogyro, or ASW liaison equipped, the ship will not carry out ASW. (Example: Ooyodo, Chitose, Chiyoda, BBVs)
Night Battle	Firepower + Torpedo + Effective Bonus (Firepower) + Effective Bonus (Torpedo)	This is the formula for all ships participating in night combat (including Standard Carrier Wo-Class Flagship and Light Carrier Nu-Class Flagship). Formation Damage Modifier and Engagement Form Modifier does not apply (exception: ASW damage in a Night Battle Only node applies both).

The effective bonus comes from improving equipments, see that page for details.

Pre-Cap Modifiers

These are the factors directly applied to your ship's attack power.

Formation Modifier (see "Damage modifier")
Engagement Modifier
Health Modifier
Bonus Against Installation
ASW Synergy
Night Attack Modifier

Effects from the modifiers are multiplied cumulatively. Formation Modifier, Engagement Modifier, and Health Modifier are applied sequentially.

Ship's Health Modifier

Damage	Modifier
Minor damage (小破, Shōha^?) or less	100%
Moderate damage (中破, Chūha^?)	70%
Heavy damage (大破, Taiha^?)	40%

These modifiers do not affect Aerial Combat.

Bonus Against Installation

Equipped with	Modifier
Type 3 Shell	250%
WG42 (Wurfgerät 42)	?%
Neither	100%

This bonus applies against Installation-Type abyssal ships.

ASW Synergy

Equipped Both Depth Charge and Sonar?	Modifier
Yes	115%
No	100%

Having 2 sets of sonars and depth charges does not increase the synergy bonus.

Night Attack Modifier

An example of a cut-in

Certain Equipment setups have a chance to trigger special attacks at night, giving boost to both attack power and accuracy. This stage is usually the most rewarding / dangerous because both sides have drastically increased attack power.

The ship must be able to participate in the night battle in order to trigger the special attacks.

Type	Modifier	Notes
Special Attack (Double Attack and Cut-In Attack)	120% for Double Attack. Varies for Cut-In Attack depending on type. See here for details.	Any misses on Cut-In Attack and Double Attack becomes scratch damage instead. Damage cap applied to each attack separately for Double Attack and Cut-In Attacks that calculates damage twice (such as Torpedo Cut-In).
Normal	100%
Anti-Submarine	0% for regular map nodes Formation Modifier for Combined Fleet battle nodes and Night Battle nodes.	This results in scratch damage against submarines during normal night battles. Engagement Form modifiers will apply for Combined Fleet battle nodes and Night Battle nodes.

Light Cruiser Fitted Gun Bonus

This is a bonus incorporated when the fitted gun system on light cruisers was introduced. Details may change as more testing is done. [math]\displaystyle{ \text {Light Cruiser Fitted Gun Bonus} = \sqrt{\text{# of Equipped Lightweight Naval Guns }} + 2 \times \sqrt{\text{ # of Equipped Lightweight Twin Gun Mounts}} }[/math] This bonus applies to light cruisers (CL), torpedo cruisers (CLT), and training cruisers (CLp), and this bonus counts the following guns:

Lightweight Naval Guns: 14cm Naval Gun, 15.2cm Naval Gun
Lightweight Twin Gun Mounts: 14cm Twin Gun Mount, 15.2cm Twin Gun Mount, 15.2cm Twin Gun Mount Kai

Example: A ship equipped with a 14cm Naval Gun, a 15.2cm Twin Gun Mount, and a 15.2cm Twin Gun Mount Kai gets a bonus of [math]\displaystyle{ 1 \times \sqrt{1} + 2 \times \sqrt{2} \approx 3.8 }[/math]

Some items to note:

Pre-Cap Modifiers do not apply to this bonus, but this bonus applies before attack cap is calculated.
15.5cm Triple Gun Mount (Main), 15.5cm Triple Gun Mount (Secondary, OTO 152mm triple extended machine gun and the such are not counted for the purpose of this bonus.
The bonus provided will be lower compared to when the ship is equipped with multiple 20.3cm Twin Gun Mount (and its variants), so please keep that in mind.

Attack Power Cap

Applies after the pre-cap modifiers. This is a soft limit on your effective attack power.

Condition: If your Attack Power Before Cap exceeds:

150 for Day Battle,
300 for Night Battle, or
100 for Anti-submarine attacks,

then the Attack Power Cap will kick-in, reducing attack power. The calculation is:

[math]\displaystyle{ \text {Cap-Adjusted Attack Power} = x + \sqrt {\text {Attack Power Before Cap} - x} }[/math], where x represents the attack power cap applicable to the attack.

Daytime Attack Cap (150) often makes it important to utilize Artillery Spotting since they boost your attack power after the cap, while Night Combat can be very dangerous and/or rewarding due to having a very high cap (300) and the summation of torpedo and firepower being used to calculate the base attack power.

Critical Modifier

All attacks have a chance to be a critical hit (although bombing during aerial battle has significantly lower chance to do so). The damage modifier applies after the cap.

Attack Type	Modifier
Normal Attack	100%
Critical Hit	150%

A few notes:

Any attack that deals 40 or more damage always display as critical damage regardless of whether it actually is a critical hit or not.
Any attack that deals 14 or less damage never display as critical damage even if the attack actually is a critical hit.
If an attack is determined to be a critical hit, the attack cannot be evaded (the evasion check happens after the critical hit check).
A rounding-off takes place after Critical Modifier is calculated, prior to calculating the other Post-Cap Modifiers shown below.

Post-Cap Modifiers

In damage calculation, Post-cap modifiers apply after the cap, but before enemy armor reduction. Thus they are very effective approach to boost your damage output (esp. against heavy armor enemies).

Currently, the post-cap modifiers are from:

Contact (Opening air strike)
Artillery Spotting (a.k.a. Day time special attacks)
AP Shell

Contact

Contact takes place during the Aerial Combat phase. It increases bombing damage for all allied bombers.
When successful, an image of the squadron performing contact is shown in the opposing fleet's formation indicator, with the text "触接中".
Trigger conditions:

More air control than Air Denial
At least one carrier scout plane, seaplane scout, or torpedo bomber equipped.

Seaplane bombers, Type 3 Spotter, and Ka-type Autogyros cannot perform contact.

It's thought that each carrier scout plane, seaplane scout, and/or torpedo bomber slot equipped is given a chance to trigger contact. Once successful, the bonus applied is chosen at random with weighting from all eligible equipped planes.

Different types of planes have different trigger rates. They are roughly estimated as (if only one is equipped):

Type	Contact Rate
Torpedo Bomber	~2%
Night Scout	~5%
Seaplane Scout	~20%
Carrier Scout	~50%

Contact Damage Modifier

The damage increase depends on the +accuracy bonus of the squadron performing contact.

Accuracy Bonus	Damage Modifier
+0	112%
+1	112%
+2	117%
+3	120%

Notes

Type 2 Recon Aircraft is useful in the case that the bombing damage bonus is desired while not removing the chance for T-disadvantage, due to its high trigger rate.
With contact, the maximum attack power of bombing (before defense, critical and ammo) is around 180. With some luck, it's possible to sink even Ru-class Flagships (Armor = 99) in one strike without a critical.

Artillery Spotting

Certain equipment setups provide a chance to trigger special attacks during day battle, giving boost to both attack power and accuracy. The damage modifiers are applied after the cap (150), thus very effective against heavily armored targets. Note that the ship requires at least 1 seaplane on board to perform Artillery Spotting (and thus will not trigger if all the seaplanes are shot down).

AP Shell

When either Type 91 AP Shell or Type 1 AP Shell is equipped alongside a large caliber gun, damage against certain ship classes are increase. The effect works also for enemies in Exercises (PvP).
Eligible targets in which this bonus applies are BB, FBB, BBV, CA, CV, Demon (Oni), Princess (Hime), Fortress. Demon (Oni) and Princess (Hime) include the subtypes of War Demon (War Oni) and War Princess (War Hime) as well as Installation-type enemies, but may exclude Destroyer Princess and Light Cruiser Demon. Unknown whether the bonus applies to armored carrier (Taihou) or CAV.

Equip Combination		Modifier
+ +	+	108%
		108%
		110%
		115%
	+	114~115%?
	+	115~116%?

Remaining Ammo Modifier

Remaining Ammunition	Modifier
50% or more	100%
40%	80%
30%	60%
20%	40%
10%	20%
0%	Scratch Damage

More specifically, the modifier is [math]\displaystyle{ \min \{ 100 \%, 2 \times \text {% of Ammo Remaining} \} }[/math]
The Remaining Ammo Modifier affects all phases, including the opening Aerial Combat Phase.
At the end of the combat, 20% of Maximum Fuel is consumed for all ships. Depending on whether both day and night battle phase occurred, either 20% (if only Day or Night battle occurred) or 30% (if both Day and Night Battle occurred) of Maximum Ammo will be consumed.
When entering night battle (from day), the Remaining Ammo Modifier on a vessel remains same as the day battle.
Even if you do not engage in night battle along the way, if the boss node is the 5th battle of the sortie, the damage dealt is dramatically reduced. It is even worse if it's the 6th (or later!) battle, as you can only deal scratch damage. Either scenario will dramatically reduce the chance of you winning.
- An example of the latter scenario would be 2-4's northwest route. Because node G is a combat node if coming from D, the boss battle ends up being the 6th battle. This is the primary reason why players typically end the sortie early if sent on that route.
- This is also the reason to avoid night battles and maelstroms along the way when trying to win at a boss node.
  - Whirlpools will decrease either or of your deployed fleet, which can be disadvantageous in long sorties. Equipping one or more ships with RADAR can help reduce losses taken.
Submarine-only nodes on limited-time event maps do not consume ammo in Day or Night Battle.

Player Damage Taken

While the above formulas and statements are generally true for damage taken by a player's ships, there are additional limits that apply to friendly units only.

For ships entering battle at chūha (orange) or higher HP:

Damage taken cannot reduce HP below 1 (i.e. ship cannot sink).

At 1 HP, any further hits will become misses.

For flagships, as well as ships with 20 morale or more (i.e. not red face):

If the incoming damage is greater than or equal to current HP, it is instead reduced to 50%-79% of current HP, rounded down.

For attacks with multiple hits (such as night battle torpedo cut-in attacks), each hit is calculated separately (and reduced if appropriate).

Combat Equipment Setup

See Artillery Spotting for day-time attack setups.
Night Battle Special Attacks
Common Setups
Full Setup List

Night Battle Special Attacks

Night battle special attacks allow your ship to double attack (DA) and cut-in (CI) at night. These special attacks are less demanding on the conditions, but more reliable and powerful than artillery spotting in the day.

Requirement

Ability to act at night
Current HP > 25% of Max HP
Certain equipment setup (see below)

Set up and Attack Modes

Different set ups have chances to trigger different modes of attack. Attack modes are only determined by the prerequisite. Any auxiliary equipment (AP shell , seaplane , AA gun , etc.) can be added without changing the attack mode.

Attack Mode	Notes on the Remaining Slots	Damage Modifier	Trigger Chance
Double Attack	No additional , or .	120% x 2	~99%
Double Attack	Any number of additional allowed.	120% x 2	~99%
Double Attack	Any number of additional allowed. Up to 1 additional allowed.	120% x 2	~99%
Cut-In (Mixed)	Up to 1 additional allowed. Any number of additional allowed.	130% x 2 (simultaneous)	Luck based
Cut-in (Sec. Gun)	No additional	175%	Luck based
Cut-in (Main Gun)	+ Any	200%	Luck based
Cut-in (Torpedo)	+ Any	150% x 2 (simultaneous)	Luck based

When your set up fulfills the prerequisite for multiple attack modes, the one closer to the bottom of the list will be considered.
If two simultaneous attacks are made, the total damage is displayed together but the Damage Cap (and Enemy Armor reduction) is applied separately to each attack.
When either DA or CI is not triggered by chance, the ship will just do a normal single attack.

Night Double Attack Chance

Has a very high (~99%) and relatively consistent activation chance. ~~Activation rate decreases with damage states~~ (source required), but is not dependent on luck. This typically results in more consistent and higher average damage than cut-in setup for ships with normal luck values.

Night Cut-in chance

[math]\displaystyle{ (\text{Luck} + \text{Placement Modifier} + \text{Health Modifier} + \text{Searchlight Modifier} ) \% }[/math]

In the old formula, it was Luck × 0.85.

Either diminishing returns or a hard cap on luck over 50 for torpedo cut-ins. (source 1, 2)

Therefore, the torpedo CI chance for Yukikaze (60 luck) would be around the same level as Shigure (50 luck).

Either diminishing returns or a hard cap on luck over 40 for three gun cut-ins. (source)

Therefore, ships with high luck will suffer from 5~10% lower cut-in chances when using the 3 gun cut-in setup compared to two-torpedo.

Either diminishing returns or a hard cap on luck over 60 for mixed cut-ins (source 1, 2)

Modifier		Value
Placement	Flagship	(+25)
Placement	Other	+15
Health	Little or no damage	0
	Minor damage (小破 Shōha)	(+5)
	Moderate damage (中破 Chūha)	+20
Searchlight	Allied	+5
Searchlight	Enemy	-10
Star Shell	Allied	+5
Star Shell	Enemy	-10

According to various reports, the exact values of flagship and minor damage modifiers are still in controversy. The mean values are shown in brackets, with deviation of +/- 5.

Anti-Sub Warfare

Any enemy submarines will force Destroyers, Light Cruisers, and Torpedo Cruisers to target them. Cut-In and Double Attacks are ignored. In normal Night Battles, ASW damage is scratch damage only. In battles starting at night, Formation Modifiers apply.

Common Setups

Destroyers

Function	Slot 1	Slot 2	Slot 3	Slot 4	Notes
General Use	Main Gun	Main Gun	Auxiliary	-	12.7cm Twin Mount Type-B Kai 2 can be substituted for 10cm Twin High-angle Mounts, and are especially effective after being improved and equipped onto a high-firepower destroyer like Yuudachi or Ayanami. Otherwise, 10cm Twin High-angle Mounts or 10cm Twin High-angle Mount + Anti-Aircraft Fire Directors are preferred for their fleet AA defense modifier, though the latter is difficult to obtain.
High-Luck Night Battle	Torpedo	Torpedo	Torpedo or Auxiliary	-	Auxiliary equipments typically are equipped on destroyers; however, luck-based destroyers benefits the most from adding an additional torpedo to their equipment in terms of night battle damage output. Candidates for night battle cut-ins without luck modernization include: Yukikaze, Hatsushimo, Shigure, Ayanami, and Ushio.
Anti-Sub Warfare	Sonar	Sonar	Depth Charge	-	On maps with few subs, or where you don't need to kill the subs, two main guns and a sonar in the third slot are useful.
Anti-Air Cut-In	High-angle Gun	Anti-Aircraft Fire Director	Anti-Air RADAR	-	Akizuki and Teruzuki can perform anti-air cut-ins without a fire director; they only need either two high-angle guns or a high-angle gun and an AA RADAR.
Ship-Specific Armaments	Slot 1	Slot 2	Slot 3	Slot 4	Notes
Yuudachi/Ayanami	Main Gun	Main Gun	RADAR	-
Hatsushimo	Torpedo	Main Gun	Anti-Aircraft Fire Director	-	Some ships boast dual utility, like Hatsushimo, who has high luck and AA. These ships can be outfitted for mixed cut-ins instead of torpedo to better utilize their AA capability (Not to say they can't be equipped conventionally with two torpedoes).
Akizuki/Teruzuki	High-angle Main Gun	High-angle Main Gun	Anti-Air RADAR	-

Light Cruisers

Light Cruisers gain access to the Medium size Main guns to buff their firepower as well as seaplanes (with a few exceptions with regards to seaplanes, those being CLTs, Isuzu Kai Ni, Yuubari and both of the Tenryuu class), making Artillery Spotting setups feasible and effective against moderately armored enemy vessels.
For light cruisers facing enemy fleets, a setup with 2 Main guns and a Seaplane ( ) offers a potent double attack in both daytime Artillery Spotting and Night Battle.
For fleets without air power, one medium main gun and two 15.5cm Triple Gun Mounts ( ) will maximize firepower while maintaining double attacks in Night Battle
The special class of the Torpedo Cruisers deserves some mention here: their specialty lies in their torpedoes and should almost always be equipped with a Type A Ko-hyoteki (to enable opening torpedo strikes). To diversify their damage output, typically two medium main guns and/or 15.5cm Triple Gun Mounts are equipped to increase shelling damage and enable Night Battle Double Attacks ( ).

Before a Torpedo Cruiser's final remodel, due to limited slots it's advisable to use Type A Ko-hyoteki and a torpedo ( ) to make the most of their preemptive attack.

Heavy Cruisers

Heavy Cruisers see the introduction of 4 slot setups after remodeling and all of them feature the ability to launch seaplanes for artillery spotting. While they are still limited to the Medium main guns, their higher firepower and armor can make them solid combatants when Battleships are unavailable or overkill.
The go-to setup for most situations will be the 2 main guns, RADAR, seaplane setup ( ) which provides day and night double attack potential.
Certain Event bosses take additional damage when a ship is equipped with Type 3 Shells. Type 3 Shell ( )
Heavy cruisers Myoukou and Prinz Eugen have high base luck, allowing reliable torpedo or mixed cut-ins at night. , is recommended for day-time artillery spotting and potent mixed cut-ins at night.

Battleships

Battleships feature a selection of Heavy Main Guns and massive resulting firepower in addition to the potent Armor Piercing shells which can cause brutal critical hits. Setups for battleships are similar to those of heavy cruisers, with one notable addition.
The Armor Piercing Shells that battleships have access to allows for the highly effective 2 Main gun, AP Shell, Seaplane setup ( ) which has a more effective Artillery Spotting Cut-In, while providing better stats than secondary guns.
Note: Official tweets state that overuse of cannons larger than what a BB is meant for will make it "overweight" and incur a "minor" accuracy penalty. (I.e. Too many 46cm or even 41cm cannons on Fast Battleships such as Kongou-class and Bismarck.)
As with Heavy Cruisers, the Type 3 Shell setup ( ) is effective against installation-type/land base enemies.

Carriers

Planes. Enough Fighters to achieve Air Superiority or Supremacy, fill out with Torpedo Bombers on larger slots for preemptive bombing damage and/or Dive Bombers on smaller slots for shelling damage.
Torpedo Bombers and Dive Bombers are roughly equivalent to each other. While Torpedo Bombers have the advantage in the preemptive aerial bombing, their damage are dependent on number of surviving planes, making air superiority very important for them. In cases where Air Superiority is not feasible, using more Dive Bombers may prove more effective.
It is possible to equip Secondary Guns like the 15.5cm Triple Gun Mount or the special SCAMP to increase the carrier's range and put it higher in the Range Order shelling phase, which can be very useful for prioritizing the CV(L) damage when in a DD heavy fleet.
To save bauxite (especially in exercises against other fleets), a combination of two 15.5cm Triple Gun Mount and/or SCAMP with a Saiun and a single bomber in the 4th slot can allow powerful shelling attacks at the cost of opening airstrike potency ( ).

Full Setup List

What follows is an extensive list of possible equipment setups related to Artillery Spotting and Night Battle attacks.
Yellow: Cut-In or Double Attack Possible

Two Slots

Equipment			Day Battle	Modifier	Night battle	Modifier
As no 2 slot setup can trigger special attacks during the day, 2 slot setups are primarily night combat focused.
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Double Attack	120% x 2
	-	-	Single Attack	100%	Double Attack	120% x 2
	-	-	Single Attack	100%	Cut-In (Mixed)	130% x 2
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Double Attack	120% x 2
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%
	-	-	Single Attack	100%	Single Attack	100%

Three Slots

Equipment		Day Battle	Modifier	Night battle	Modifier
Day Combat Focus
	-	Double Attack	120% x 2	Double Attack	120% x 2
	-	Cut-In	110%	Double Attack	120% x 2
	-	Single Attack	100%	Cut-In (Mixed)	130% x 2
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Double Attack	120% x 2
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
	-	Single Attack	100%	Single Attack	100%
Night Combat Focus
For Night Combat setups, see Day Combat 4 slot setups below and ignore the seaplane. The Day attack will be a Single Attack at 100%.

Four Slots

Equipment	Day Battle	Modifier	Night battle	Modifier
Day Combat Focus
	Double Attack	120% x 2	Cut-In (Gun)	200%
	Double or Cut-In	120% x 2 or 110%	Cut-In (Gun)	175%
	Double Attack	120% x 2	Cut-In (Mixed)	130% x 2
	Double Attack	120% x 2	Double Attack	120% x 2
	Double or Cut-In	120% x 2 or 150%	Double Attack	120% x 2
	Cut-In	110%	Double Attack	120% x 2
	Cut-In	110%	Cut-In (Mixed)	130% x 2
	Cut-In	120%	Double Attack	120% x 2
	Cut-In	130%	Double Attack	120% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Mixed)	130% x 2
	Single Attack	100%	Cut-In (Mixed)	130% x 2
	Single Attack	100%	Single Attack	100%
	Single Attack	100%	Single Attack	100%
	Single Attack	100%	Single Attack	100%
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
Night Combat Focus
	Single Attack	100%	Cut-In (Gun)	200%
	Single Attack	100%	Cut-In (Gun)	200%
	Single Attack	100%	Cut-In (Gun)	200%
	Single Attack	100%	Cut-In (Gun)	175%
	Single Attack	100%	Cut-In (Gun)	175%
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Cut-In (Mixed)	130% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Double Attack	120% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2
	Single Attack	100%	Cut-In (Torpedo)	150% x 2

Victory Conditions

Damage Gauge calculation: (Sum of enemy fleet HP reduced) / (Sum of enemy fleet HP at start of combat) × 100% In PvP, even those considered "sunk" are treated as having 1HP remaining for gauge calculation. (This is clearly visible against a submarine fleet.) Higher conditions have higher priority on this list. Unless specified, the condition assumes no friendly ship sunk.

Perfect S

All enemy ships sunk and Enemy Damage Gauge is 0%.

In PvP, no damage taken and all enemy ships considered "sunk".

S (Victory)

All enemy ships sunk.

If any friendly ship is sunk, it is B Victory instead.

In PvP, all enemy ships "sunk".

If any friendly ship would be considered "sunk", then it would be a B Victory instead, as well.

A (Victory)

Required number of enemy ships sunk.

In this case damage gauge does not matter.
Enemy flagship does not need to be sunk.
Cannot happen if enemy fleet consists of only 1 ship.

B (Tactical Victory)

Note: This rank is the minimum requirement to clear maps without boss gauge.
Enemy flagship sunk (in this case damage gauge does not matter)
Enemy flagship alive, A victory condition not met, Damage gauge at least 2.5 times of the enemy damage gauge.
Enemy flagship alive, friendly ship sunk, A victory condition met, Damage gauge at least 2.5 times of the enemy damage gauge.
Enemy flagship alive, friendly ship sunk, A victory condition not met, Damage gauge at least 3 times of the enemy damage gauge (multiplier in question)
Enemy flagship sunk, friendly ship sunk, number of friendly ships sunk < number of enemy ships sunk.

C (Tactical Defeat)

Enemy flagship alive, Damage gauge higher than enemy gauge but not reaching 2.5 times as much.
Enemy flagship alive, friendly ship sunk, A victory condition met, Damage gauge higher than enemy damage gauge but not reaching 2.5 times as much.
Enemy flagship alive, friendly ship sunk, A victory condition not met, Damage gauge higher than enemy damage gauge but not reaching the multiplier required for B Victory (see 4th B Victory condition)
Enemy flagship sunk, friendly ship sunk, number of friendly ships sunk ≥ number of enemy ships sunk. (Note that maps with boss gauges, such as 4-4, 5-3, event maps, etc, can be cleared under this condition.)

D (Defeat)

Enemy took less than a certain amount of damage (Own gauge is less than 0.05%).

Both sides taking 0 damage is also D.

Enemy flagship alive, damage gauge lower than enemy gauge (C is possible under this condition if both sides have a high gauge)
Enemy flagship alive, friendly ship sunk, damage gauge lower than enemy gauge, but not fulfilling E loss condition.

E (Defeat)

Enemy flagship alive, over a certain number of friendly ships sunk. (see below)

Notes

The Minimum Sunk Requirement:

4 ships out of a fleet of 6
3 ships out of a fleet of 5
2 ships out of a fleet of 4
2 ships out of a fleet of 3
1 ship out of a fleet of 2

Victory status affects the chance of getting drops and rare drops on the specified node.

B rank or above is necessary to obtain drops.
A rank or above is typically necessary for obtaining rare drops.
S rank has a higher chance of obtaining rare drops than A rank, and is required for some very rare drops.

Additional Explanation/Details

↑ Source: 艦これ-チラ裏検証- / 夜戦陣形と命中回避 (Jan 1, 2015). Currently the hit rates only apply on nodes starting with night battle (eg. 5-3-C). In addition, please be aware that given limited sample sizes from the exp't, the measured hit rates by using different formations are NOT differing on a large scale, thus using "higher / lower" not simply "high / low".
↑ Source: 半製造BSｱﾚｺﾚ雑記帳 / 「艦これ」砲撃命中率について・複縦陣中間報告 (Dec 5, 2014). If more relevant sources are discovered please add them in.

zh:战斗

[NBacc-1] Source: 艦これ-チラ裏検証- / 夜戦陣形と命中回避 (Jan 1, 2015). Currently the hit rates only apply on nodes starting with night battle (eg. 5-3-C). In addition, please be aware that given limited sample sizes from the exp't, the measured hit rates by using different formations are NOT differing on a large scale, thus using "higher / lower" not simply "high / low".

[DL_SAcc-2] Source: 半製造BSｱﾚｺﾚ雑記帳 / 「艦これ」砲撃命中率について・複縦陣中間報告 (Dec 5, 2014). If more relevant sources are discovered please add them in.

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