Shield (stat)

Version 0.30: This article may not be up to date for the latest stable release of Crawl.

This page is about the Shield stat. For shields in general, see Shields. For the player skill, see Shields (skill).

SH is one of your three physical defenses, along with AC and EV. It allows you to completely negate physical attacks (both melee and ranged) and some magical attacks. Unlike AC and EV, you have no innate SH score. SH gained from wearing a physical shield is governed by the Shields skill; magical shields are unaffected by that skill.

Sources

The following items/abilities can increase your SH:

• Wearing a shield; bucklers, kite shields, and tower shields, in ascending order of effectiveness and cumbrousness
• Wearing an amulet of reflection, Brooch of Shielding, or ring of the Octopus King
• Having the Large Bone Plates mutation
• Using The Shining One's Divine Shield
• Qazlal's Storm Shield passive

Blocking

You can block melee attacks (inc. reaching attacks) and non-penetrating "projectiles" - these include ranged weapons and certain spells like Iron Shot or Poison Arrow.

What can't be blocked by SH:

• Penetrating attacks: Javelins, Bolt spells, Starburst...
• Almost everything with perfect accuracy: Magic Dart, Smiting, Chain Lightning, Explosions (Fireball, Damnation), Shatter...

(Orb of Destruction is the only spell that ignores EV but can be blocked)

• Enchantments: Agony, Pain, Confuse, everything that checks willpower

Calculation

If you are wielding a physical shield, its SH is determined as follows:

• Your Base SH is determined by type of shield. 3 for bucklers, 8 for kite shields, 13 for tower shields.
• Add Skill Bonus of (base_SH/40 + 0.19) * skill.
  • Add another 0.57 if skill ≥ 3, else add 0.19 * skill.
• Add Stat Bonus of DEX * 38 * (base_SH + 13) / 5200.
• Add Enchantment value. +1 enchantment = +1 SH.
• Add 0.25 SH.

All other sources of SH (Qazlal shield, amulet of reflection...) are flat bonuses, and are added on top of the physical shield bonus. The final value is rounded to the nearest integer and displayed as the player's SH value.

If you are paralysed, petrified, or if dexterity is 0, then SH is set to 0 regardless of any other factors.

To-hit vs SH

The game compares the attacker's "pierce value" to the defender's "block value".

The attacker's pierce value is dependent on their to-hit (accuracy) and the type of attack:

• Melee attack: 1d(15 + to_hit/2 + 5×past_blocks^2)
• Ranged attack: 1d(1.3×to hit + 5×past_blocks^2)

The defender's blocking value is equal to:

• All attacks: 2d(2×SH)/6 - 1.3
• Divide by 3 against melee attacks from invisible oponents.

If the blocking value is greater or equal than the attacker's pierce value, the attack is blocked.

Strategy

SH is less effective per point than EV; EV succeeds if 2d(2 * EV - 1)/2 > 1d(to-hit + 1) - 1, it doesn't decay against multiple attacks, and it defends against penetrating attacks. However, shields give a high amount of SH - wearing a shield almost certainly gives more SH than the EV you lost. Also, blocking is unaffected by armour encumbrance.

The main costs of wearing the shield are the inability to wield two-handed weapons, and the shield penalties (which can be reduced and eventually reduced with Shields skill).