Rules Bit (GURPS): Shields and Cover

Intro: Under Cover

This rule looks at the matter of letting shields provide cover instead of a DB bonus. That option offers some interesting benefits, from a nicely-restored (in 4e) ability for shields to protect passively, to detailed protection by body location, to shield walls and other defensive tricks. It all meshes nicely with existing game rules for cover, too.

The rule

In general, treat shields as offering only their DB, per written rules. But whenever the GM thinks it sensible, treat shields as cover (B407) instead:

  • A shield treated as cover offers a TH penalty equal to the shield’s DB, instead of adding DB to Active Defenses, for any attack against which DB would be effective.

Defending

Cover provides powerful protection, but there’s a trade-off: a shield protects with either its cover or its DB, not both at once. 

If the shield protects as cover and the TH penalty causes the attack to fail, then the attack struck the shield, with no additional action on the part of the defender.

If the shield protects as cover but the attack succeeds anyway, then the attack strikes some area not covered by the shield. The defender can attempt any normal defense, even a Block – but Active Defenses do not get the added bonus of DB.

Example: You hold a shield with DB 3. If you treat this as cover, enemy attacks take -3 to hit you. An attack that fails by 4 or more misses you entirely. An attack that fails by 1 to 3 strikes the shield. An attack that succeeds bypasses the shield and may hit you. You can attempt any valid Active Defense, but without the +3 bonus from shield DB! 

Variants and options

Ways to treat cover

Below are three different ways to game shields as cover. Note that the options below allow for extra-high DB from unusually large shields, or from curling up behind a shield. These are fun combat options not offered in standard GURPS; see Shields and Size for the Games Diner’s take.

1. Abstract cover

This simply places a name on the core rule above: DB becomes a TH penalty versus any location on the target. To keep things easy, specific effects on individual hit locations aren’t considered. 

2. Random cover

An alternative to the above: Per B408, you can give attacks a random chance of striking cover, instead of applying a TH penalty. For example, rather than a -2 TH penalty, half cover applies a 50/50 chance (4-6 on 1d6) that the attack will hit the cover.

Here’s an expansion of that, letting shields provide random cover to the defender as a whole:

No cover: Doesn’t significantly hide target. No effect. Example: DB 0 “shield”.
Slight cover: Hides 1/3 or less of the target. Treat as -1 TH, or as 2 in 6 chance of striking cover. Example: DB 1 shield.
Half cover: Hides about 1/2 of the target. Treat as -2 TH, or as 3 in 6 chance of striking cover. Example: DB 2 shield.
Good cover: Hides 2/3 or so of target. Treat as -3 TH, or as 4 in 6 chance of striking cover. Example: DB 3 shield.
Excellent cover: Hides most of target. Treat as -4 TH, or as 5 in 6 chance of striking cover. Example: DB 4 shield.
Full cover: Hides all of target. Example: DB 5+ shield.

If the attack randomly hits the shield’s cover, then it whacked into the shield with no Active Defense roll needed. Otherwise, the attack misses the shield’s cover. Proceed with Active Defense or damage . . .

3. Specific cover

This is yet another alternative to the above: a shield grants full, half, or no cover to individual hit locations, not to the defender as a whole. For generic shield shapes:

DB 0: No significant protection for any location.
DB 1: Half cover for shield arm/hand (full cover for shield hand if buckler) and torso/vitals.
DB 2: Full cover for shield arm/hand; half cover for torso/vitals/groin.
DB 3: Full cover for shield arm/hand and torso/vitals/groin; half cover for legs (but not feet).
DB 4: Full cover for shield arm/hand, torso/vitals/groin, and legs (but not feet).
DB 5+: See All about full cover below.

Locations not mentioned above have no cover and can be targeted normally. An attack on the foe’s weapon hand or face, for example, is a normal attack at the usual penalty for hit location.

Locations with half cover can be attacked with difficulty: treat as -2 TH (on top of any normal TH modifier for hit location), or use random cover with half cover (3 in 6 change of hitting the shield instead of attacking the hit location).

Locations with full cover cannot be directly attacked; an attempt to do so automatically hits the shield.

Ambitious and detail-hungry GMs could further expand specific cover effects, using the entire range of possible coverage (no, slight, half, good, excellent, full) for each hit location, or further modify per-location coverage for shield position (i.e., vary coverage for a high, “normal”, or low shield position), or tweak per-location coverage for odd shield shapes. I leave those to the interested!

Lessening the DB penalty

However and whenever you treat a shield as cover, there’s a trade-off: the benefit of cover is balanced by loss of the DB bonus to Active Defense. That’s simple, though arguably a bit harsh on the defender. 

If you agree, let DB apply half its usual bonus (round down) to Active Defenses, instead of no bonus, when a shield is treated as cover.

The net effect may be to boost the defensive power of shields a bit beyond standard GURPS, but not wildly so. Try it out.

All about full cover

While a defender cannot actively wield a shield with DB of 5 or more, he can hide behind it to gain full cover for all hit locations. As above, this means the locations cannot be hit. Game big (or effectively big) shields as follows. (The rule for DB 3 shields is official GURPS; my rules for bigger shields are not.) 

A DB 3 shield is already clumsy: wielders take -2 TH on melee attacks (B547, under “Attacker’s Situation”) unless they have special training (Shield-Wall Training, Martial Arts 51).

A DB 4 shield applies a -2 on all combat skills (not just melee TH), which applies -1 to Parry and Block as well. Also apply -2 to Vision rolls and -1 to Dodge. Let Shield-Wall Training reduce the combat skill and Vision penalties to -1.

DB 5 fully covers the defender, if not optimally. The shield cannot be used for active defense, which makes it a one-man pavise (see GURPS Low-Tech p. 116). It provides full cover from the front center hex only, if the defender remains still. Attacks from the left/right front hexes, lobbed attacks, or any shield wielder movement render cover incomplete: treat as excellent cover (-4 TH, or 5 in 6 chance of striking cover).

DB 6 allows full cover from any front hex and even allows minimal wielder movement behind the shield. (Whether and how the wielder can prop up such a huge shield in the first place is a GM call.)

At DB 7 and larger, we’re talking big propped-up walls behind which the defender has plenty of room to move – in other words, mantlets (GURPS Low-Tech p. 116). Handle accordingly.

The GM will rule on any special considerations. A melee fighter could run behind a covering shield to get at the defenseless wielder – or possibly even reach his weapon over the top of the shield from the front. A very small fighter behind a large propped-up shield may have full cover versus enemy shooters, with room to move about too – but if he pops out from behind cover to return fire, he’ll be partially exposed in that instant. And so on.

Protection and facing

Per written rules, a shield offers protection only versus attacks from the wielder’s front center hex and shield-side hex. It provides no protection – DB or cover – vs attacks from the weapon-side hex, side hexes, or rear hex.

An exception: As described above, DB 5 and larger shields used as full cover can provide full or partial cover from all three front hexes.

Cover and flails

It would make sense to reduce the cover value of a shield vs a flail or similar hard-to-block weapon. Use the Block penalty as an effective decrease in levels of coverage, i.e., a reduction in the TH penalty.

Example: A flail that gives a -2 to Block attempts treats a shield offering good (-3 TH) cover as offering only slight (-1 TH) cover.

Notes for GURPS 3e

All of these rules will work with GURPS 3e too, with one change: Subtract 1 from a shield’s PD, and use that as DB in the above rules.

Example: A medium shield offering PD 3 in 3e has DB 2 in 4e terms. It acts as a DB 2 shield for all purposes above.

Connections

Shields and Size

As mentioned above, these rules work especially well with the Shields and Size rules allowing you to boost DB by hunkering down behind a shield, or by borrowing the shield of a bigger creature.

Here’s an extra nugget for users of both rules: Let Shield-Wall Training (Martial Arts p. 51) remove the left/right front hex vulnerabilities of DB 5 shields when trained wielders act in close formation (i.e., a line or circle, one man per hex). That’s the way to build an impenetrable “turtle” formation: Take large DB 3 shields, have fighters “hunker down” beneath to gain a +2 DB bonus and the full front-hex cover of effective DB 5 shields, and let Shield-Wall Training ensure that each vulnerable right/left front hex is covered by the next man. Do that in a circle, with fighters in the middle taking care of the “roof”, and you’ve got a “turtle” dome protecting every angle. SPARTAAAA!

When to use it

GM choice

When does a shield provide DB, and when does it provide cover? It’s a GM call. There’s nothing particularly wrong with the existing rules for shields and DB, but cover may play more realistically in some situations.

For example, you may like the realism of a shield providing great protection to the torso and partial protection to the legs, while leaving the head or feet fully exposed, instead of granting equal protection to all locations. Use the specific cover option.

If you don’t care for a wholesale switch to shields as cover, you might use the rules in limited instances. The full cover rules are perfect when a character wants to curl up behind a shield, a smart defense against ranged attacks like arrows or dragon fire.

Another good use for the rules is any instance in which a shield user has no Active Defense versus a ranged attack. Currently, even a large shield offers no protection against an unseen arrow in 4e, as it only aids in Active Defense. Cover rules allow a chance for passive protection too.

Example: A silent crossbow bolt streaks toward an unsuspecting knight with a DB 2 shield. Whether the arrow intentionally or randomly targets a specific hit location, the attack suffers a -2 TH (if you’re using default abstract cover), or has a 50/50 chance of striking the shield (if you’re using random cover), or attacks the head normally, the torso with partial cover, and the shield arm with no chance of avoiding the shield (if you’re using specific cover). Although the knight has no Active Defense, these options mean his shield may catch the missile.

Attacker choice

Optionally, an attacker can choose to treat a shield as cover. He’s specifically aiming to strike far from the shield’s protected areas, negating its extra protection. Using default abstract cover, that means an overall TH penalty. Using random cover, he takes no TH penalty, but stands a random chance of striking the shield. Using specific cover, he has to choose his hit location carefully.

If the attacker hits, follow rules as above: the defender can defend (and even Block) normally, but with the tradeoff of losing the DB bonus on Active Defenses.

Status

This page separates shield cover rules from an earlier page combining them with the rules for wielder size and position. Both of those, in turn, come from outdated GULLIVER rules for Shields and Size.

My old 3e rules worked fine for me, but this is an all-new update for 4e, with a few new and untested tweaks like the note on flails. It all needs more scrutiny and testing!

Designer’s notes

1. If the GM allows fighters the choice of whether to handle shields as DB or as cover, my old GULLIVER rules suggested that either the attacker or defender could make the choice. I removed the defender choice for this update; it seems more sensible that the attacker would be the one to decide, by choosing to expressly aim for uncovered areas. What do you think?

2. While we’re on that topic: It would make sense that an attacker is always trying to strike somewhere unprotected by the shield, as opposed to making a special choice to do so. But since there’s no default TH difference between hitting a shield-protected target and an unprotected one, we can assume that the default blow isn’t a particularly concerted effort to do so. The above penalized blow does mark a concerted effort to get around the shield, whatever exactly that may mean in the abstract positioning of combat.

The ruling seems even more sensible in the case of ranged combat: either you aim a shot at the target in general, in which case you might send your arrow directly into his shield; or you deliberately aim for some smaller, unprotected part. The latter is a tougher shot, but unless the target responds with a skillful Block, a successful hit guarantees you’re not haplessly plunking your missile into that darned buckler.

3. These rules let you treat a shield as cover, and optionally let an attacker bypass that cover (i.e., negate the shield’s DB) by taking a TH penalty. That all plays nicely with 4e’s written rules for cover.

But the net effect of bypassing DB by taking an equivalent TH penalty (or by aiming at an unprotected area, depending on how you play it) bumps up against one other rule: the Deceptive Attack. That action could also be employed to simulate “bypassing” shield DB – but it would charge double DB, not straight DB, as a TH penalty.

That had me thinking: Should these rules use double DB as the TH penalty for cover? Doing so would put things in line with the Deceptive Attack rules, yes – but would then conflict with the rules for cover. A half-covered target only applies a -2 TH in 4e, which seems to play nicely with the game’s 3d hit probabilities as well. Using doubled DB as a cover penalty would imply that a small DB 1 shield or cloak covers half of a human, and that a medium or large shield covers almost all of a person. That doesn’t seem right.

In the end, I favored conformance with 4e’s cover rules, as cover is the topic at hand. Yes, this means that if the GM allows you to treat a target’s shield as cover, you can essentially take a “cheap” Deceptive Attack at only -1 TH per -1 Active Defense, up to the target’s DB (further decreases in Active Defense would carry the usual, higher TH penalty). That marks a break from the standard treatment of Deceptive Attack as a way to reduce defenses.

That’s using abstract cover, though. I think specific cover plays more nicely with Deceptive Attack. You can avoid DB entirely just by attacking an unprotected location, but on the other hand, some locations will be fully protected; you can’t attack them at all. It makes for a different dynamic.

The GM could then allow Deceptive Attack, at the full -2 TH x shield DB, as a difficult way of getting at the fully protected targets – say, a sword thrust from above that goes over and behind the top of a large shield, to get at the (normally) fully-covered vitals. That preserves a special role for Deceptive Attack as a way of getting past shield protection. It’s a thought, anyway; it should be rigorously tested.

4. Comments on this article spurred the option of halving, instead of dropping, a shield’s DB bonus on Active Defense when the shield acts as cover. In play, this means an attacker taking a TH penalty to bypass a shield’s cover reduces the shield’s Active Defense bonus by half that amount (ignoring rounding). (Example: if you take a -4 TH to bypass a DB 4 shield’s cover, the shield wielder does get a DB bonus on his followup Active Defense, though only a +2, not the full +4.)

In other words, the option brings mechanics back in line with Deceptive Attack. The act of taking a TH penalty to bypass a shield’s cover can be considered simply a specific application of Deceptive Attack.

Wrapping Up

The above offers a lot of shield stuff for the GM toolbox, but there are decisions to be made: when to treat shields as cover instead of DB, and which treatment of cover to use (abstract, random, or specific).

What looks useful, not-so-useful, or just plain broken in there?

6 Comments

  • joncarryer

    I like this train of thought, but I would go even further and allow the shield DB to be used in both active and passive roles. My reasoning is this; a warrior armed with a shield is going to be harder to hit just as he is, with no active effort on his part, as the shield will provide cover to some portion of his body. The larger the shield, the more of his body will be covered. However, if the attacker attempts to hit some part of him that isn’t covered, no warrior with any training at all is just going to say “Oh well, it was worth a try, but he’s not aiming for the part of me that I’m holding the shield over, so what can I do?” No, he’s going to do his best to interpose the shield between him and the incoming attack, and the larger the shield, the less effort this will require, hence the easier it will be to succeed. Thus, I believe that it’s reasonable and realistic to allow the shield’s DB to have some effect in both the passive role, as cover, and the active role, as a modifier to the Block attempt.

    • tbone

      Well, it’s hard to make the case either way without specifying which options are in place (as I tossed out quite a few…) But to provide a simple response, imagine the generic GURPS case in which a shield just provides generic DB protection, with no special consideration of body parts, etc. To that, we want to add a simple option for treating the shield as cover (TH penalty). With that in mind, I get the point you make, but it raises two game play problems:

      1) The shield creates the TH penalty, and keeps its DB bonus. We’ve doubled the defensive power of a shield.

      2) If the treatment of the shield as cover is meant to be an option for the attacker, there’s no reason for the attacker to use it. Why take the TH penalty to avoid the shield, when the result remains an unchanged skill+DB Block roll for the defender? Where’s the benefit?

      Hence my rule, as it avoids the two problems above. As for the ease of blocking an attack that takes the cover TH penalty, my thinking was that, with the attack expressly defined as coming toward some unshielded location, it’s really just the edge of the shield closest to the weapon that matters for purposes of meeting the blow; the remainder of the shield, no matter how big, isn’t going to matter much.

      BUT: Does “not matter much” mean “not matter at all”? Arguably, you’re quite right; the size should matter some. If nothing else, a large shield’s “edge that matters” is likely to be closer to the incoming blow than a buckler’s edge would be. Even if full DB weren’t added to the Block, some size-based modifier to the Block sounds reasonable (after all, even a few weapons gain size-related Parry mods, despite not having DB).

      I think a good compromise answer suggests itself: when a blow successfully uses the cover option to avoid a shield, the subsequent Block gets only half its DB. That lessens both of the problems I point out above. And, interestingly, it also meshes perfectly with Deceptive Attack: as it now requires -2 TH to reduce Block DB by 1, avoiding a shield’s “cover” becomes essentially one specific instance of Deceptive Attack.

      What do you think?

      • joncarryer

        Mea culpa. I should have stated to begin with that the one of your many options that strikes me as the most reasonable and workable is “specific cover”. That being said, I think this addresses the issue of double jeopardy; there is no problem of allowing the shield to provide both a TH penalty and a DB bonus to Active Defence, as there is no TH penalty in this option. In fact, it addresses both of the problems you raised. Either the shield covers the area being aimed at or it doesn’t, with regard to passive cover. If it doesn’t, then the defender gets to try to shift the shield so that it does cover the target and, as you say, the larger the shield, the less movement is likely to be needed to shift it to where it will be effective.

        However: my arguments only hold for that one option. I agree that in the more generic options, where the efectiveness of cover is abstracted into a TH penalty, then it would be fair to halve the DB bonus to Active Defence, to avoid the double jeopardy that you point out.

        Finally, I would like to clarify that I would only use these rules if I was also using the Damage to Shields rules, which would offset any increase in the defensive power of shields by turning an automatic negation of damage to a situation in which high amounts of damage might still pass right throught the shield and affect the targeted body part to some lesser extent.

        • tbone

          You’re right that specific cover creates no new TH penalty; there are only the TH penalties that the unprotected locations present anyway. Yet without some counteracting defensive penalty, that factor does boost the power of shields. It denies the attacker some targets and forces the selection of specific targets, often with severe TH penalties. If the defender also gets to keep full DB, then shields just got more powerful.

          I see, though, that you note this power increase and suggest using the Damage to Shields rule to mitigate it. I agree: the ability of specific cover to automatically, completely protect a body part is too generous for sheer realism, when such a fully-covered part should still be vulnerable to attacks that go through the shield. Good call.

          So if the GM is using the specific cover rules but doesn’t want to all-round boost shields’ defensive power, one of the following seems in order: add the Damage to Shields rule (realistic!), or drop the DB bonus on Block (per my main suggestion; easy, but perhaps too severe), or halve the DB bonus on Block (per my less-severe suggestion above).

          Thanks for the comments! The added thoughts are making these rules better.

          Edit: With these comments in mind, I made some small tweaks to the writing in the rules. The main change: I added the option for halving, instead of dropping, the DB bonus on Active Defense. The final notes add commentary on how this plays with Deceptive Attack.

  • Esteemed Visitor

    About hit locations….

    A buckler could completely cover a foot, a knee, a groin, a neck, a face, a skull….

    All depends on where you opt to hold it.

    A ready maneuver should cover changing rest position but that is costly.

    I would allow it in place of a “step” too.

    Or as a free action combined with a strike or a defense if you take a -2 to skill (-1 defense) penalty for multitasking, as per Move and Attack.

    • tbone

      Right, that’s something I admit to not detailing in the article: modifying hit location-specific coverage to reflect shield position, as opposed to always assuming a single, standard shield position. As you note, a shield could be placed to give a specific hit location better coverage, even full coverage if the shield size is at least as large as the hit location size.

      It’s similar in concept to older rules for “concentrated defense” (see here and here), though those published rules are pretty abstract, addressing generic defenses and broad target areas, as opposed to our topic here (i.e., much more specific concentrated shield coverage based on shield size vs target size).

      How to game the use of a shield to cover any selected specific target area? It’s easy enough to let a defender do this on a Ready maneuver; from there, just apply coverage rules per my article. (The GM will have to make calls on whether or not the desired hit location gets full or partial coverage, and what sort of coverage adjacent hit locations will get.)

      But how about doing this without a Ready? If it’s a matter of, say, quickly placing a buckler in front of your face in response to a blow coming at the face, well, I think that’s just a normal Block attempt. But if you were to, say, attack with a sword and, at the same time, reposition your shield to a head-protecting high position because you expect that’s where the reprisal will come… As you suggest, that sounds like a multitasking feat, similar to attacking with two weapons (though not as difficult, I’d think).

      How to game it, in terms of the penalties to place on one or both of the actions? I haven’t really thought about it…

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