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Accuracy and EvasionEdit

During sorties, whether an attack connects or not is heavily dependent on the attacker's accuracy and the opponent's evasion:

  • Icon Hit : The accuracy of a ship, which determines how accurate your shots are. Keep in mind that this stat is hidden and there is no in-game way to see how much accuracy your ship has.
  • Icon Evasion : The evasion of a ship, which determines how high the chances are that you will evade an attack. Each attack calculates the evasion differently, but in all cases, evasion stat will suffer from diminishing returns past a certain point. Attacks that are evaded will be displayed as miss.

The following formulas are subject to change as further research is published.

Hit RateEdit

The actual hit rate can be calculated as follows:

First, the Base Hit Rate is calculated. This takes into account the attacker's Accuracy Value against the target's Evasion Value. Each type of attack (e.g. shelling, torpedo, airstrike) has its own formula for calculating its Accuracy Value.

\text{Base Hit Rate} = \text{Accuracy Value} - \text{Evasion Value}

Afterwards, the Base Hit Rate undergoes through two caps, which prevents it from exceeding or falling lower than certain thresholds. This is determined by:

\text{Capped Hit Rate} = \operatorname{cap_{2}} \Big ( \operatorname{cap_{1}} \left ( \text{Base Hit Rate} \right ) \cdot \text{Morale Modifier} \Big )

Observations:

  • The Morale Modifier is a value depending on the target's morale state:
    • \text{Morale Modifier} = \begin{cases} 0.7, & \text{ if Morale} \geq 53 \\ 1.0, & \text{ if } 32 < \text{Morale} < 53 \\ 1.2, & \text{ if } 20 < \text{Morale} \leq 32 \\ 1.4, & \text{ if Morale} \leq 20 \end{cases}
  • \operatorname{cap_{1}} \left ( x \right ) = \begin{cases} 10, & \text{ if } x < 10 \\ x, & \text{ otherwise } \end{cases}
  • \operatorname{cap_{2}} \left ( x \right ) = \begin{cases} 96, & \text{ if } x > 96 \\ x, & \text{ otherwise } \end{cases}

Finally, the Final Hit Rate can be calculated, which is directly used to determine the likelihood of that attack hitting (with normal or critical hit) or missing:

\text{Final Hit Rate} = \Big ( \big \lfloor \text{Capped Hit Rate} \big \rfloor + \text{Proficiency Bonus} +
 1 \Big ) \%

The probability of a normal hit is then:

\text{Normal Hit Rate} = \left ( \text{Final Hit Rate} - \text{Critical Hit Rate} \right ) \%

While the probability of a miss is:

\text{Miss Rate} = \left ( 100 - \text{Final Hit Rate} \right ) \%

Critical Hit RateEdit

Abbreviating Capped Hit Rate as H;

\text{Critical Hit Rate}(\%) = \begin{cases} \big \lfloor 1.3\sqrt{H} \big \rfloor + \text{Proficiency Bonus} + 1, & \text{ for Shelling } \\ \big \lfloor 1.5\sqrt{H} \big \rfloor + 1, & \text{ for Torpedo } \\ \big \lfloor 0.2\sqrt{H} \big \rfloor + \text{Proficiency Bonus} + 1, & \text{ for Airstrike } \\ \big \lfloor (1.5 + \text{Night Contact})\sqrt{H} \big \rfloor + 1, & \text{ for Night Battle } \\ \big \lfloor 1.3\sqrt{H} \big \rfloor + 1, & \text{ for Shelling (Support) } \\ \big\lfloor 0.2\sqrt{H} \big \rfloor + 1, & \text{ for Aistrike (Support) } \end{cases}

Observations:

  • Always less than Final Hit Rate (usually less than Normal Hit Rate).
  • Night Contact refers to the bonus provided by the Type 98 Reconnaissance Seaplane (Night Recon), if it successfully triggers during Night Battle. If Night Contact occurs, this takes a value of 0.7; otherwise it is 0.

Accuracy ValueEdit

Shelling AttacksEdit

The shelling formula determines the hit rate and the evasion of shelling attacks. Note that this applies to both regular shelling and carrier shelling, but it does not apply to night battles.

\text{Accuracy Value} = \Big \lfloor \left ( \left ( 90 + 2\sqrt{N_{s}} + \sqrt{1.5L_{s}} + E_{s} \right ) \cdot F C + W_{s} \right ) \cdot B_{1}B_{2} \Big \rfloor

Where:

  • N_{s} is the ship's level
  • L_{s} is the ship's luck
  • E_{s} = \sum^{\text{All Slots}} E_{acc} + E_{m} \sqrt{\bigstar}
    • E_{s} is the total accuracy provided by the ship's equipment
    • E_{acc} is the equipment's displayed accuracy stat
    • E_{m} is the equipment's improvement modifier for shelling accuracy
  • W_{s} is the ship's fit bonus or overweight penalty
    • Check out this page for more info.
  • F is the fleet's formation modifier:
    • F = \begin{cases} 1.0, & \text{ for Line Ahead, Diamond} \\ 1.2, & \text{ for Double Line, Echelon, Line Abreast } \\ ???, & \text{ for Cruising Formation 1 (Anti-Sub)} \\ ???, & \text{ for Cruising Formation 2 (Forward) } \\ ???, & \text{ for Cruising Formation 3 (Ring) } \\ ???, & \text{ for Cruising Formation 4 (Battle) } \end{cases}
  • C is the ship's morale modifier:
    • C = \begin{cases} 1.2, & \text{ if Morale} \geq 53 \\ 1.0, & \text{ if } 32 < \text{Morale} < 53 \\ 0.8, & \text{ if } 20 < \text{Morale} \leq 32 \\ 0.5, & \text{ if Morale} \leq 20 \end{cases}
  • B_{1} is the Artillery Spotting accuracy modifier. Applies only when an Artillery Spotting attack is triggered.
    • B_{1} = \begin{cases} 1.1, & \text{ for Double Attack } \\ 1.3, & \text{ for Secondary CI } \\ 1.5, & \text{ for Secondary CI (Radar) } \\ 1.2, & \text{ for AP CI } \\ 1.3, & \text{ for AP CI (Secondary) } \end{cases}
  • B_{2} is the AP Shell accuracy modifier. Applies according to certain equipment combinations:
    • B_{2} = \begin{cases} 1.1, & \text{ for AP + Main } \\ 1.25, & \text{ for AP + Main + Radar } \\ 1.2, & \text{ for AP + Main + Secondary } \\ 1.3, & \text{ for AP + Main + Secondary + Radar } \end{cases}

Additional notes:

  • Combined Fleet modifiers appear to be flat penalties but are still subject to further investigation.
  • Incomplete: Combined Fleet modifiers are missing.

Torpedo AttacksEdit

The formula which determines the hit rate and evasion of all forms of torpedo attacks during the day. This formula does not apply during night battle.

\text{Accuracy Value} = \left ( 85 + 2\sqrt{N_{s}} + \sqrt{1.5L_{s}} + E_{s} + \frac{P_{s}}{5} + B_{s} \right ) \cdot F C

Where:

  • N_{s} is the ship's level
  • L_{s} is the ship's luck
  • E_{s} = \sum^{\text{All Slots}} E_{acc} + E_{m} \sqrt{\bigstar}
    • E_{s} is the total accuracy provided by the ship's equipment
    • E_{acc} is the equipment's displayed accuracy stat
    • E_{m} is the equipment's improvement modifier for torpedo accuracy
  • F and C (formation and morale modifiers) assume the same values as in the Shelling Attack formula.
  • P_{s} is the ship's effective torpedo power, or in other words, the ship's Basic Attack Power for torpedo attacks after the attack power cap and all pre-cap modifiers have been applied.
    • For more information, visit this page
    • Of note is that due to this, factors such as the ship's health state and the current battle's engagement form will have an effect on torpedo accuracy.
  • B_{s} is the ship's innate torpedo accuracy. All player ships have 0 innate torpedo accuracy, but certain enemy vessels may have values above 0.

Anti-Submarine WarfareEdit

The formula which determines the hit rate and evasion of attacks performed against submarines. It can be a depth charge attack or an aerial attack, as long as the target is a submarine.

\text{Accuracy Value} = \left ( 80 + 2\sqrt{N_{s}} + \sqrt{1.5L_{s}} + E_{s} + 2A_{sonar} \right ) \cdot F C

Where:

  • N_{s} is the ship's level
  • L_{s} is the ship's luck
  • E_{s} = \sum^{\text{All Slots}} E_{acc} + E_{m} \sqrt{\bigstar}
    • E_{s} is the total accuracy provided by the ship's equipment
    • E_{acc} is the equipment's displayed accuracy stat
    • E_{m} is the equipment's improvement modifier for ASW accuracy
  • F and C (formation and morale modifiers) assume the same values as in the Shelling Attack formula.
  • A_{sonar} is the sum of the ASW stats of every Sonar that the ship is equipping. Improvements are not considered here.
    • In other words, this means that every Sonar offers a hidden, ASW-specific accuracy boost equal to double of its displayed ASW stat.

Opening AirstrikeEdit

The formula which determines the accuracy and the evasion against the Opening Airstrike that is performed by bombers during the opening phase. Unlike other attacks, the accuracy of airstrikes is not affected by morale.

\text{Accuracy Value} = 95

Night BattleEdit

The formula which determines the hit rate and evasion during a night battle. During a night battle, all attacks are treated the same, regardless of shelling or torpedo attacks.

\text{Accuracy Value} = \left ( N_{1} \left ( 69 + E_{a} \right ) + 2\sqrt{N_{s}} + \sqrt{1.5L_{s}} + E_{s} \right ) \cdot F C M + E_{b} + N_{2} + W_{s}

Where:

  • N_{s} is the ship's level
  • L_{s} is the ship's luck
  • E_{s} = \sum^{\text{All Slots}} E_{acc} + E_{m} \sqrt{\bigstar}
    • E_{s} is the total accuracy provided by the ship's equipment
    • E_{acc} is the equipment's displayed accuracy stat
    • E_{m} is the equipment's improvement modifier for night battle accuracy
  • W_{s} is the ship's fit bonus or overweight penalty. The values used here are those applying specifically to night battle.
  • F and C (formation and morale modifiers) assume the same values as in the Shelling Attack formula.
  • M is the night battle special attack modifier.
  • M = \begin{cases} 2.0(??), & \text{ for Double Attack } \\ 1.1, & \text{ for Mixed CI } \\ 1.65, & \text{ for Secondary CI } \\ 1.5, & \text{ for Triple Gun CI } \\ 1.5, & \text{ for Torpedo CI } \end{cases}
  • E_{a} is the Star Shell bonus. Assumes a value of 5 if the Star Shell activates; is 0 otherwise.
  • E_{b} is the Searchlight bonus. Assumes a value of 7 if a Searchlight is active; is 0 otherwise.
  • N_{1} is the Nightscout modifier. Assumes a value of 1.1 if Night Contact has occurred; is 1.0 otherwise.
  • N_{2} is the Heavy Cruiser night battle bonus, as follows:
    • If equipped with a 20.3cm Twin Gun Mount: N_{2} = 10
    • If equipped with a 20.3cm (no.3) Twin Gun Mount: N_{2} = 15
    • Bonus is applied only once regardless of the amount of applicable guns equipped on the ship.
    • Notably, the lower 20.3cm bonus overrides the higher 20.3cm no.3 bonus if both are equipped on a ship, resulting in only +10. Therefore, equipping a 20.3cm plus a 20.3cm no.3 should be avoided.

Evasion ValueEdit

\text{Base Evasion Value} = \left \lfloor \left ( V_{s} + \sqrt{2L_{s}} \right ) \cdot F \right \rfloor

Where:

  • V_{s} is the ship's displayed evasion (including equipment)
  • L_{s} is the ship's luck
  • F is the fleet's formation modifier. Refer to this table for a list of applicable formation modifiers according to the respective combat phases.

Abbreviating Base Evasion Value as E;

\text{Capped Evasion Value} = \begin{cases} E, & \text{ if } E < 40 \\ \left \lfloor 40 + 3\sqrt{E - 40}\right \rfloor, & \text{ if } 40 \leq E < 65 \\ \left \lfloor 55 + 2\sqrt{E - 65} \right \rfloor, & \text{ if } E \geq 65 \end{cases}

\text{Evasion Value} = \Big \lfloor S \cdot \left ( \text{Capped Evasion Value} + I + C - \text{Fuel Penalty} \right ) \Big \rfloor

Where:

  • I is the sonar improvement evasion bonus, applying only against opening and closing torpedo attacks. Assume 0 otherwise.
    • I = \left \lfloor \sum^{\text{All Sonars}} 1.5 \sqrt{\bigstar} \right \rfloor
  • S is the Searchlight evasion penalty. Becomes 0.2 if it is night battle and the ship is equipping a Searchlight (disregarding whether it is active or not); otherwise assume 1.0.
  • C is the Heavy Cruiser / Aviation Cruiser evasion bonus. Applies only during night battle and if the ship is a CA(V), in which case it becomes 5. Assume 0 otherwise.
  • \text{Fuel Penalty} = \begin{cases} 75 - R, & \text{ if } R < 75 \\ 0, & \text{ otherwise } \end{cases}
    • R is the ship's remaining fuel percentage, expressed as an integer (e.g. 60% fuel remaining equals 60)

List of Factors affecting Accuracy or EvasionEdit

This list displays factors that have an effect on accuracy and evasion of your ships in general. Due to the complexity of accuracy and its factors, it will be using the following format to list them:

  • Factor: The factor which influences the accuracy or evasion in some way.
  • Affected Type: Here, it is noted, which form of attack is affected:
    • Shelling: Shelling attacks during the day, including carrier shelling.
    • Torpedo: All forms of torpedo attacks during the day.
    • ASW: Anti-Submarine Warfare attacks during the day.
    • Airstrike: Opening Airstrike attacks performed by bombers during the opening phase.
    • Night: All forms of attacks that take place during the night.
    • ALL: The factor affects all forms of attack.
    • ?: In case it is still unknown which attack that the factor affects, or if there is a suspicion that it affects phases other than what is currently displayed, a question mark will be used.
  • Description: A brief explanation as to how the factor affects the accuracy or evasion.

The evasion list will only contain the Factor and Description headers in its table, due to it being less complex than the accuracy formula.

The list is only a summary of factors with a brief explanation of their effects, it will not contain any in-depth explanations regarding their application in the actual formulas. In case that is what you're looking for, you are recommended to check out the formulas above instead.

Note: Keep in mind that the list might not be complete, this will be updated in due time if more is known about the factors.

Factors affecting AccuracyEdit

Factor Affected Type Description
Ship Level

Shelling
Torpedo
ASW
?

Accuracy increases as you level up, but with diminishing returns.
Luck Icon Luck

Shelling
Torpedo
?

A tiny amount of accuracy can be obtained via Luck Icon Luck , albeit with very heavily diminishing returns.
Critical Hit ALL A critical hit will never miss regardless of the hit rate.
Morale/Fatigue

Shelling
Torpedo
ASW
Night

Ships with 32 or less morale will suffer an accuracy penalty, while ships with 19 or less morale will suffer heavier penalties. On the other hand, increasing your morale above 52 will give you an accuracy bonus.
Engagement Modifier Torpedo The engagement modifier affects the accuracy of torpedo attacks.
Equipment Improvement

Shelling
Torpedo
?

Certain equipment has been shown to increase accuracy proportional to the square root of its improvement level, with different equipment giving accuracy bonuses to different attacks.
BB Fit/Overweight Gun

Shelling
Night

Equipping battleships with fit guns gives them an accuracy bonus. Likewise, equipping battleships with overweight guns gives them an accuracy penalty instead. The fit and overweight guns are different for each battleship class and model.
AP Shell Shelling Using AP Shells together with large-caliber main guns increases accuracy against heavily armored enemy ships and installations.[1]
CA Fit Gun Night Heavy/Aviation Cruisers get increased Night Battle accuracy when equipped with certain 20.3cm model guns.
CL Fit Gun

Shelling
?

Using certain "Fit Guns" (i.e. 14cm and 15.2cm mains) on Light Cruisers will improve their accuracy.[2]
Formation ALL Each formation has its own modifier that affects each attack differently.
Artillery Spotting Shelling There is a high accuracy increase observed for Cut-ins, even with low Morale.
The increase is lower for Double Attacks.
Night Special Attacks Night Just like Artillery Spotting during the day, a high accuracy increase has been observed for night Cut-in attacks.
Likewise, the increase is observed to be lower for Double Attacks.
Night Battle Equipment Night Star Shell
Star Shell 101 Card
s [3] and Searchlight
Searchlight 074 Card
s[4] increases the accuracy of the whole fleet when activated.
ASW Equipment ASW Icon ASW stat on a Sonar increases the accuracy against submarines.[5]
Combined Fleet

Shelling
?

Surface Task Force: accuracy -0.40 for the main fleet and about -0.15 for the escort fleet in Cruising Formations 2 and 4.
Carrier Task Force: normal accuracy for the main fleet and about -0.35 accuracy for the escort fleet in Cruising Formation 4.[6]
Ship Class

Shelling
?

Light Cruisers have about 2% lower accuracy than other ship classes.[7]

Factors affecting evasionEdit

Factor Notes
Luck Icon Luck A tiny amount of evasion can be obtained via Luck Icon Luck , albeit with very heavily diminishing returns.
Evasion stat Ship's evasion stat, which includes the evasion you receive from using the equipment. Evasion has diminishing returns past a certain amount.
Formation Each formation has its own modifier that affects each attack differently.
Morale/Fatigue Ships with 32 or less morale will suffer an evasion penalty, while ships with 19 or less morale will suffer heavier penalties. On the other hand, increasing your morale above 52 will give you an evasion bonus.
Sonar Improvements Improving sonars will increase your evasion against torpedoes. Keep in mind that this only applies to torpedo evasion during the day.
Fuel modifier Any ship with a fuel percentage that is lower than 75% will start suffering evasion penalties.

NotesEdit

The above formulas are based on the reverse engineered Vita formulas[8][9], which are believed to work for the browser version well enough. However, not all details were fully tested for the browser, differences may exist as well[10][11]. For the previous formulas based on data verification, see[12][13].

ReferencesEdit

  1. https://twitter.com/KanColle_STAFF/status/520461746943696896
  2. https://twitter.com/KanColle_STAFF/status/600208207454146561
  3. https://twitter.com/KanColle_STAFF/status/479862934768582656
  4. https://twitter.com/KanColle_STAFF/status/438562857513254913
  5. https://twitter.com/KanColle_STAFF/status/438574201809543168
  6. http://kankoregouchin.blog.fc2.com/blog-entry-60.html
  7. https://twitter.com/Xe_UCH/status/819905394864570370
  8. https://docs.google.com/document/d/1tqYyqzdc1RT_fYDKFMcUId0kOZHCdGpVsObm6yt-Yco
  9. https://twitter.com/Nishisonic/status/890202416112480256
  10. https://docs.google.com/spreadsheets/d/1hEyic8JurL04jdhiTCfitCtf8pBCkoENKwsyO3KZzDQ
  11. https://docs.google.com/spreadsheets/d/1_JSx84fkL4z89jwe-mol5AHFhldDdLwSuMqSrjsWwrQ
  12. WikiWiki page on Accuracy and Evasion
  13. http://bs-arekore.at.webry.info/201502/article_4.html