Shield Skill

Shield skill is a combat skill that determines a player's ability to activate an equipped shield to block an incoming physical attack. When a physical attack is successfully blocked by a Shield, the damage taken from the attack is significantly reduced.
*Shields can block any physical attacks coming from the front of the player
*The player does not need to be engaged to an enemy to block an attack.
*All shields have a hidden game statistic: Shield Size.
**While not viewable in game, it is programmed into the game to each individual shield and can be seen on the individual wiki pages for each shield.
*The amount of damage reduction from a successful shield block is based on the shield size, its DEF, Damage Taken, and Shield Defense Bonus.
**PercentDamageBlocked = SizeDamageReduction + ShieldDEF / maxShieldItemLevel, 99 - 99 / 10 + 2
***Only the listed DEF value on the shield itself and its augments are included in ShieldDEF. No other source of DEF is factored in.
***Some simplified values for the ShieldDEF contribution to block damage reduction.
****Use ShieldDEF/2 for non-ilvl shields. 
****Use ShieldDEF/4 for ilvl 119 shields.
****Use the full formula for ilvl 100~118 shields.
**FinalDamageTaken = IncomingBaseDamage - ShieldDefenseBonus 1 - PercentDamageBlocked/100 1 - PDT/100
***Where PDT is the sum of "Physical Damage Taken -%" and "Damage Taken -%" from gear, up to the gear cap of 50.
**The total damage reduction from Shield blocks is not subject to the -87.5% cap on Physical Damage Taken.
*A shield's block rate is determined by the attacking enemy's combat skill (determined by their level), the shield's Size Base Block Rate, and the player's shield skill, such that:
**BlockRate = SizeBaseBlockRate + ShieldSkill - AttackerCombatSkill 0.2325
**0.2325 is the average skill:block rate conversion over all skill ranges. For example, some skill levels the conversion factor is 0.25, for others it is 0.2.This average is used as all the Shield Skill:Block Rate tiers are currently unknown and this yields fairly accurate observable results.
**The spell Reprisal and the Job Ability Palisade artificially increases the shield block rate by a set percent independent of the above formula.
* An Attackers Combat Skill can be determined by reversing the block rate formula using your Known block rates from parsing.
**AttackerSkill = ((-1 (ActualBlockRate - SizeBaseBlockRate) 0.2325) + ShieldSkill
***where ActualBlockRate is equal to your Parsed unmodified block rate, and is greater than 5%, but less than 100%. it is impossible to determine attacker skill above or below those thresholds due to the minimum and maximum rate for blocking. 
***When obtaining this value in parsing, Use a substantial data set, without block rate gear, and without gear changing for the length of the parse. 
*Ultimate shields do not follow normal rules regarding block rate and damage reduction. See the table below or their individual pages.
*The job trait Shield Mastery prevents the casting of spells from being interrupted by a physical attack if all hits while casting are successfully blocked and allows successful blocks to generate additional TP return for the player.
Standard Shields
Shield Size	Base Damage Reduction	Base Block Rate
1 	-20% 	55%
2 	-40% 	40%
3 	-50% 	45%
4 	-65% 	30%
Ultimate Shields
Shield	Total Damage Reduction	Base Block Rate
 	-75% 	50%
 	-60% 	~108%
==Shield Skill Caps==
Job	Grade	Level 49	Level 99
PLD	A+ 	150 	424
WAR	C+ 	139 	378
WHM	D 	133 	334
BST	E 	124 	300
RDM	F 	114 	265
THF	F 	114 	265
==Equipment Bonuses==
Item 	Level	Slot 	Jobs 	Amount
Fighter's Mufflers +1	74 	Hands 	WAR 	15
Gallant Leggings +1 	74 	Feet 	PLD 	12
Acheron Shield +1 	75 	Shield 	WAR RDM DRK BST BLU 	11
Ker's Mask 	99 	Head 	WAR PLD DRK DRG 	11
Testudo Mantle +1 	99 	Back 	WAR MNK RDM THF PLD DRK BST BRD RNG SAM NIN DRG BLU COR DNC	11
Acheron Shield 	75 	Shield 	WAR RDM DRK BST BLU 	10
Boxer's Mantle 	70 	Back 	All jobs 	10
Fighter's Mufflers 	54 	Hands 	WAR 	10
Gallant Leggings 	52 	Feet 	PLD 	10
Master Shield 	52 	Shield 	WAR WHM RDM THF PLD BST SAM 	10
Rogue's Culottes 	56 	Legs 	THF 	10
Steadfast Shield 	99 	Shield 	PLD DRK 	10
Testudo Mantle 	99 	Back 	WAR MNK RDM THF PLD DRK BST BRD RNG SAM NIN DRG BLU COR DNC	10
Warlock's Boots 	52 	Feet 	RDM 	10
Warlock's Boots +1 	74 	Feet 	RDM 	10
Creed Armet +2 	85 	Head 	PLD 	7
Fazheluo Radiant Mail	90 	Body 	WAR PLD DRK BST SAM DRG 	7
Shield Torque 	65 	Neck 	All jobs 	7
Fazheluo Mail +1 	90 	Body 	WAR PLD DRK BST SAM DRG 	6
Kaiser Schaller 	73 	Head 	WAR PLD 	6
Skeld Sword 	90 	Weapon 	WAR PLD DRK 	6
Creed Armet +1 	85 	Head 	PLD 	5
Fazheluo Mail 	90 	Body 	WAR PLD DRK BST SAM DRG 	5
Knight's Earring 	72 	Earring	All jobs 	5
Koenig Schaller 	73 	Head 	WAR PLD 	5
Light Buckler 	40 	Shield 	WAR WHM RDM THF PLD BST SAM 	5
Portus Annulet 	94 	Ring 	All jobs 	5
Sinfender 	69 	Weapon 	PLD DRK 	5
Storm Shield 	70 	Shield 	WAR WHM RDM THF PLD BST SAM 	5 (Assault)
Pilferer's Aspis 	30 	Shield 	All jobs 	5 (THF Sub job)
Shield Belt 	30 	Waist 	All jobs 	5 (PLD Sub job)
Buckler Earring 	35 	Earring	All jobs 	3
Creed Earring 	90 	Earring	PLD 	3
Fortified Chain 	60 	Neck 	All jobs 	3
Mu Necklace 	75 	Neck 	All jobs 	3 (Salvage)
Shotel +1 	42 	Weapon 	WAR THF PLD DRK SAM DRG BLU 	-3
Shiva's Shotel 	72 	Weapon 	WAR THF PLD DRK SAM DRG BLU 	-5
Shotel 	42 	Weapon 	WAR THF PLD DRK SAM DRG BLU 	-5
Agelast Torque 	99 	Neck 	All jobs 	15
Combatant's Torque 	99 	Neck 	All jobs 	15
==References==
*Shield Skill vs. Block Rate Testing (Martel, BG/FFXIAH)
*Block Rate Unified Formula Testing (Showmo, FFXIAH)
*Size 1+2 Block Rates (Martel, BG/FFXIAH)
Category:Combat Skills