Combat

Effects of Ship Damage
Amount of damage on a ship will affect its performance.

Aerial Combat
Aerial Combat Stages

Fighter Combat
$$\text {Fighter Power} = \sum^\text{All slots} \text{Floor(} \sqrt{\text{Number fighters in slot}} \times \text {Plane anti-air bonus} \text{)}$$

Fighter planes, fighter-bombers (bombers with +AA stat), and seaplane bombers participate in Fighter Combat.

The allied fleet and enemy fleet's Fighter Powers are compared to determine the result of Fighter Combat:
 * EFP: Enemy Fighter Power, FP: Fighter Power. Abbreviated to save space.
 * This calculation does not take into account any anti-air weaponry equipped on ships. Carrier anti-air stat is also not considered.
 * The percentage of planes shot down applies for both sides' respective outcomes, and is calculated per slot.
 * For example, securing Air Superiority means allied planes shoot down up to 80% of enemy planes, and the enemy under Air Incapability will shoot down up to 40%.
 * Contact can be triggered by having at least 1 carrier scout plane, seaplane scout, and/or torpedo bomber equipped.  It increases damage during the bombing phase depending on the accuracy bonus of the squad performing Contact.
 * Even if allied planes secure air supremacy, planes can still be lost (up to 10%), and the subsequent anti-air defense stage can eliminate bombers regardless.
 * If enemy fleet launches no fighters, while the allied fleet launches any planes, the result defaults to Air Supremacy.  If both sides launch no planes, then the rest of the battle is treated the same as if Air Parity was achieved.

Fleet Anti-air Defense
Each enemy bomber slot is assigned at random to a defending ship. Those ships then, for each assigned enemy slot, have an approximately 50% chance to shoot down enemy planes. The number of planes shot down is given by the equations below:

$$\text{Planes Shot Down} = \text{Floor((Ship AA } + \text{Floor(Fleet Anti-air Bonus} \times \text{Formation Modifier))} \times 0.2125\text{)}$$ $$\text{Fleet Anti-air Bonus} = \text{Floor(} \sum^\text{All slots}\text{Equipment AA Bonus} \times \text{Equipment Modifier)}$$ "Fleet Anti-Air Bonus" is the sum of every equipment slot of every ship in the fleet (including the defending ship).

Equipment Modifiers

 * Any equipment that gives an anti-air bonus will contribute to shooting down enemy bombers.
 * The ship chosen to defend against bombers is not necessarily the ship targeted by that slot.
 * The ship selected to defend is not necessarily the target of the bomber.  Any allied ship, including submarines, may be chosen to defend against bombers.
 * The forward sliding and machine gun animations seem to have no correlation with the calculations.
 * These calculations only apply for the allied fleet's anti-air defense; enemy fleets seem to use a different formula.

Damage Calculation
Main Formula

Basic Attack Power

Formation Modifier (Pre-Cap Modifier)

 * The surface damage modifier does not affect Aerial Combat or Anti-Submarine attacks.
 * The surface damage modifier applies to both shelling and torpedo attacks.
 * You need at least 4 ships in your fleet to select a formation. Diamond 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 low 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 night combat.

Engagement Form Modifier (Pre-Cap Modifier)
Engagement Forms
 * Please note that all engagement forms affect both sides equally, including crossing the T ( Advantage or Disadvantage ).
 * Night battle and aerial combat are not affected by engagement forms.
 * Crossing the T (Disadvantage) can be avoided by equipping a 彩雲 (Saiun) (Carrier-based recon plane).
 * Using Saiun effectively makes what would have been Crossing the T (Disadvantage) become Head-on Engagement.

Parallel Engagement

The course of the player's fleet and the enemy fleet are the same. Head-on Engagement

The course of the player's fleet and the enemy fleet are opposite each other. Crossing the T

The course of the player's fleet and the enemy fleet are perpendicular to each other (that's 90 degrees, which results in a T figure). A fleet is in disadvantage if it is coming from「｜」direction, and is in advantage it is is coming from「―」direction.

(Historically, the point of this was for the「―」fleet to bring as many guns to bear on the enemy while limiting the firepower of the enemy that can only use guns mounted forward.)

Night Combat
Night Battle Attack Types
 * 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 have taken more than moderate (orange) damage before attacking in order to participate in night battle.
 * List of Main Guns
 * List of Secondary Guns
 * Auxiliary equipment (e.g radar, sonar/depth charge, searchlight, turbine, special ammunition, pure AA equipment(green), and midget-sub) 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.
 * Formation bonuses and penalties apply in night battles, but Engagement Forms do not.  (Exception: In Nodes that begin with a Night Battle, an Engagement Form is rolled invisibly, the multiplier for which is applied to Anti-Submarine damage only.)

Cut-in Equipment Setups
NOTE: These are only a few examples. See the above table.

NOTE: Midget subs don't count as torpedoes for this.

Double Attack Equipment Setups
NOTE: These are only a few examples. See the above table.

Cut-in Attack
Note:  If two attacks (simultaneous or consecutive) are made, the total damage is displayed together but the Damage Cap (and enemy Armor) is applied separately to each attack.

Cut-in chance: (0.85 * Luck + Placement Modifier + Health Modifier + Searchlight Modifier) [%]

Double Attack
Two consecutive attacks at 120%. Very high base activation chance, compared to cut-in's luck stat reliant chance.

Ship's Health Modifier (Pre-Cap Modifier)
This modifier does not affect Aerial Combat.

Attack Power Cap (Applies After All Pre-Cap Modifiers)
Conditions for the attack power cap to activate: [Basic attack power x Pre-cap modifiers] exceeds 150 for day battle, 300 for night battle, and 100 for anti-sub attacks. This is the attack power cap, and it's represented below by $$x$$:

$$\text {Attack Power After Caps} = x + \sqrt {\text {Pre Caps Attack Power} - x}$$

Daytime Attack Cap often makes it important to utilize Artillery Spotting when possible to increase damage. Night Combat can be very dangerous and/or rewarding due to having a very high cap and the inclusion of torpedo to firepower for attack power calculation.

Critical Modifier (Post-Cap Modifier)
It should be noted that the critical message always appears when damage dealt is greater than or equal to 40, regardless of whether the 150% modifier was applied or not. On the other hand, the critical message will never appear when damage dealt is less than or equal to 14, even if the 150% modifier was applied.

Contact (Post-Cap Modifier)
Damage Modifiers Notes
 * Contact takes place during the Aerial Combat phase. It increases bombing damage for all allied bombers.
 * When successful, a 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 elegible equipped planes.
 * Different types of planes have different trigger rates. They are roughly estimated as (if only one is equipped):
 * The damage increase depends on the +accuracy bonus of the squadron performing contact.
 * 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 (Post-Cap Modifier)
Artillery spotting allows your ships with seaplanes to double attack and cut-in during day battle.
 * When the following conditions are all met for a ship, artillery spotting may occur.
 * Proper equipment (see below)
 * Air superiority or greater achieved in aerial combat phase
 * Thus, if aerial combat is not triggered, artillery spotting cannot occur.
 * Not in heavily damaged (大破) state
 * Ship is carrying at least 1 seaplane  (i.e. slots are not all at 0 remaining).


 * Factors affecting trigger chance
 * Increases with combined fleet LOS (very roughly +0.08% per LOS)
 * Flagships bonus of around +15%
 * Air supremacy adds about +10% more than air superiority
 * Seaplane bombers can be used in artillery spotting. (25/4/2014 )
 * Ka-type Observation Autogyro does not work for artillery spotting.

Attack types:

Single Attack Double Attack Cut-in Attack
 * A ship will only do a single attack if
 * only 1 main gun is equipped (e.g.).
 * no main guns are equipped (e.g. ).
 * a double attack/cut-in was not triggered by chance.
 * Damage: 100%
 * A ship can do a double attack if
 * 2 or more main guns equipped (e.g. ).
 * Damage: 120 % x 2
 * Trigger chance: ~50%

Mixed Attack
 * A ship can do a cut-in attack if
 * equipped with 1 main gun and 1-2 secondary guns (without AP shell/Radar) (e.g. ).
 * Damage: 110 %
 * equipped with 1 main gun, 1 secondary gun and 1 radar (e.g. ).
 * Damage: 120%
 * equipped with 1 main gun, 1 secondary gun and 1 Type 91 Armor-Piercing (AP) Shell.
 * Damage: 130 %
 * Cut-in attacks receive an accuracy bonus.
 * Trigger chance: ~50%
 * A ship will have a chance to do either double attack or cut-in attack if
 * equipped with 2 main guns + 1 secondary gun (e.g. ).
 * Cut-in damage:  130 %
 * Double attack damage: 120 % x 2
 * equipped with 2 main guns + 1 Type 91 Armor-Piercing (AP) Shell.
 * Cut-in damage:  150 %
 * Double attack damage: 120 % x 2
 * Trigger chance: Equally distributed, ~30% each (double attack and cut-in attack), with the remainder going towards single attack.

Notes:
 * Luck  and sparkling do not affect the trigger chance of artillery spotting.
 * Artillery spotting cut-in attacks cannot miss, but they will inflict scratch damage instead.
 * Type 3 Shell , torpedoes and machine guns  do not count toward triggering artillery spotting.
 * Tables of main guns and secondary guns

Remaining Ammo Modifier

 * In general, two bars of will be used in Day Battle for all ships, regardless of whether they attack or not.
 * The Remaining Ammo Modifier affects the opening Aerial Combat Phase.
 * When entering night battle, the Remaining Ammo Modifier on a vessel remains same as the previous day battle.  One bar of  is used for all ships in Night Battle, regardless of whether they attack or not.
 * Because most battles will consume 2 bars of ammunition each, try to engage the boss before the 5th battle, or else achieving victory becomes unlikely (but not impossible).
 * When attempting to defeat boss nodes, avoid night battles and whirlpools on the way.
 * While early maps' whirpools decrease your resources directly, later maps will decrease either  or  bars of your sorted fleet, which can be disadvantageous in long sorties.
 * Submarine-only nodes on limited-time event maps do not consume ammo in Day or Night Battle.

Victory Conditions

 * Perfect S
 * All enemy ships sunk and no damage taken.
 * S (Victory)
 * All enemy ships sunk and no allied ships sunk.
 * A (Victory)
 * Required number of enemy ships sunk (see below) and no allied ships sunk.
 * B (Tactical Victory)
 * Enemy flagship sunk and no allied ships sunk.
 * Sinking the enemy flagship guarantees at least a B as long as no allied ships are sunk.
 * Enemy flagship sunk, friendly ship sunk and number of friendly ships sunk < number of enemy ships sunk.
 * Damage gauge at least 2.5 times higher enemy damage gauge.
 * C (Tactical Defeat)
 * Didn't clear any of the conditions for A or B, but enemy took over a certain amount of damage.
 * Damage gauge higher than enemy gauge, but not reaching 2.5 times as much.
 * Friendly ship sunk, damage gauge higher than enemy, but not 2.5 times as much.
 * Friendly ship sunk, enemy flagship sunk and number of friendly ships sunk ≥ number of enemy ships sunk. It is possible to clear maps with boss gauges (eg. 4-4, 5-3, event maps) with a C if the enemy flagship is sunk.
 * D (Defeat)
 * Enemy took less than a certain amount of damage.
 * Both sides taking 0 damage is also D.
 * If your fleet consist only 1 ship and it is reaching Heavy Damage without meeting any winning requirements, it will instantly judged as D as well.
 * Damage gauge lower than enemy gauge.
 * Friendly ship sunk, not all enemy ships sunk, and gauge lower than enemy gauge.
 * E (Defeat)
 * Over a certain number of friendly ships sunk. (see below)
 * Friendly ship sunk while not meeting any victory conditions.
 * No damage done to enemy, while taking over a certain amount (Never happens in a fleet of 1).

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 victories tend to have no drops, while Perfect S has the highest chance for rare drops.