Thursday, June 23, 2011

Shields Part XXI

In a long post blackrazor demonstrated how darned effective a shield is for a platemail wearing fighter but didn't go on to evaluate how the shield holds up when people aren't wearing platemail. It's also screwed up a little by his house rules in an earlier post for dopplehanders as they are +1 to hit with 1d8 damage (making the shield a bit worse then it is). The shield and it's place in D&D combat has sure gotten a lot of attention lately, here's more on the topic.

Many folks agree heavy armor allowed the medieval warrior to ditch the shield as it's defensive value was mitigated by the effectiveness of the armor and the requirement of heavy arms to breach the heavy armor others wore, why are shields better for heavily armored fighters than they are for lightly armored fighters in D&D and related systems?

Against a foe with a thaco of 19 using a d6 weapon A fighter in plate with a shield is only likely to suffer 80% of the damage of a fighter who wears plate alone. The warrior with but a shield is likely to suffer 90.9% of the damage they would likely sustain if unarmored entirely. So shields in D&D are more effective for the heavily armored.

For my math I'm using the B/X D&D AC 6 Thaco 19 Orc with a 1d6 weapon as a foe.
Such an orc will do an average of 3.5 pts of damage a round when not accounting for the hit chance.
Orc Attack with normal AC rules
ac.....avg likely damage
2 .....0.7 - 80% the damage of plate alone
4.....1.05- 85.7% the damage of chain alone
6.....1.4- 88.9% the damage of leather alone
8.....1.75- 90.9% the damage with no armor

A fighter with a shield alone is suffering 90.9% the damage an unarmored fighter will. So why does the fighter with plate and shield get more protection out of the shield?

So is that +1 shield bonus to AC still making sense?

Number crunching on that limited set of data alone says no.

How would we fix this? Is a fix really worth it?
The straight forward fix is a shield blocks 20% of damage and doesn't otherwise effect the AC score.

Orc attack with 20% damage reduction.
AC .....avg likely damage
3* .....0.7 - 80% the damage of plate alone
3 .....0.875
5* .....0.98- 80% the damage of chain alone
5 .....1.225
7* .....1.26- 80% the damage of leather alone
7 .....1.575
9* .....1.54- 80% the damage with no armor
9 .....1.925

But a lot of people aren't quick at figuring out such math and outside sources do not use this notation. I also creates an area where shields don't block anything they just diminish hits a bit.

One could speed up the math by having a shield block a fixed amount of damage. It makes the math easier at the table top. But it also makes the shield more effective vs the typical opponent.

Lets say a shield blocks 1 pt of damage. Vs a d6 damage weapon that looks like this when hit chances are factored in

Orc attack with shield blocking 1 pt of damage
AC .....avg likely damage
3+ .....0.625 - 71% the damage of plate alone
3 .....0.875
5+ .....0.875- 71% the damage of chain alone
5 .....1.225
7+ .....1.125- 71% the damage of leather alone
7 ..... 1.575
9+ .....1.375- 71% the damage with no armor
9 .....1.925

Against orcs, goblins and 1st level fighters that 1 pt off of damage is pretty darned sweet. Certainly better than a 1 point AC adjustment as an average 3.5 hit is turned into an average 2.5 hit. Against heavier hitting creatures it's far less effective to the point of making shields pointless, but of course how much benefit would there really be with a shield against a Frost Giant? Under such a scheme it makes a heck of a lot more sense to ditch the shield and swing a two hander vs the big critters.

But such a solution changes the shield and the nature of armor in D&D and moves into into a more variant game. As the game exists now the Frost Giant (B/X version)
is thaco 11 dishing out 14 points of average damage. using the normal AC rules the damge it's likely to dish out is as follows.

Frost Giant Attack standard AC
ac .....avg likely damage
2 .....8.4
3 .....9.1
4 .....9.8
5 .....10.5
6 .....11.2
7 .....11.9
8 .....12.6
9 .....13.3

Pretty darned sweet really and without any math in play.

Frost Giant Attack with shield blocking 1 pt damage
ac avg likely damage
3+ .....8.45
3 .....9.1
5+ .....9.75
5 .....10.5
7+ .....11.05
7 .....11.9
9+ .....12.35
9 .....13.3

Not much different at all from the standard AC bonus. but it does have a tiny extra bit of math and requires a change in notation.

Frost Giant Attack with shiled blocking 20% damage
ac avg likely damage
3* .....7.28
3 .....9.1
5* .....8.4
5 .....10.5
7* .....9.5
7 .....11.9
9* .....10.64
9 .....13.3

wow the 20% reduction in damage is hella-good. but does that make sense? Why is the shield protecting the fighter better against a much more massive blow then a typical blow. Some might love it, I think it's unsatisfying certainly when one factors in the math slow down and the notation change. The only way to settle up the impact is to complicate the game more by having more rules for shields with say a damage cap on hits they could block but this slows down the game even more.

Shields blocking 1 pt of damage looks pretty good and it certainly boost the effectiveness of the shield at the lower man vs man scale without throwing heavy hitters out of balance later. Is it worth it? There's micro math and notation that must be kept. I myself have folks keep track of AC with and without shield so it's not a huge deal there. But what about magic shields?

If a normal shield blocks 1pt of damage should a magical shield block more damage or simply improve AC? If it improves AC while normal shield blocks 1 pt of damage there is a logic break in what a shield does in the game. If it improves how many points of damage are blocked the results are pretty large at the shallow end of the pool.

Orc attack with +1 shield blocking 2 pt of damage
AC avg likely damage
3++ .....0.375
3 .....0.875
5++ .....0.525
5 .....1.225
7++ .....0.675
7 ..... 1.575
9++ ..... 0.825
9 ..... 1.925
much much better then the bonus granted to AC in the standard system.

Frost Giant Attack with +1shield blocking 2 pts damage
ac avg likely damage
3++ ..... 7.8
3 .....9.1
5++ ..... 9
5 .....10.5
7++ .....10.2
7 .....11.9
9++ .....11.4
9 .....13.3
not too far off from the AC bonus in the standard system.

The points blocked scales very well with tough monsters compared to normal AC system but it's very much superior against common foes and there's the rub, PCs dish out damage like common foes. But, how often do PCs fight NPCs with magic shields? Are we gaining much by deviating from the standard system?

How much is changing the game worth for a change in shields? It really depends on where yuo want your game to go and how different you feel like being.

Here's one of those pesky hobgoblins the reality check. Shields block a heck of a lot of blows. Maybe more so in fake combat than on real combat but it's hard to say that definitively as people attacking you when you are armed with a shield in fake combat aren't really afraid of getting maimed or killed (I've seen people injured but very seldom compared to the number of blows struck). In my experience a shield easily blocks half or more of the blows struck against a combatant.

How to model that experience? Why with a saving throw of course. Use the save vs paralysis or turn to stone for classes trained to use a shield according to a character's level. If untrained count as 0-level for the save. This of course changes things up a lot.

Orc Attack with shield save agaisnt 1st level fighter
ac avg likely damage
5 .....1.225
7@ .....1.024
7 .....1.575
9@ .....1.25
9 .....1.925
Certainly effective vs orcs.

Frost Giant Attack with shield save against 1st level fighter
ac .....avg likely damage
3 .....9.1
5@ .....6.825
5 .....10.5
7@ .....7.73
7 .....11.9
9@ .....8.645
9 .....13.3
Shield saves rock vs Frost giants.

When one goes up in level the shiled save will be even more telling. But what about all those abstract HP characters have aren't they supposed to reflect combat training (never mind the far less abstract healing spells)? Isn't the Shield save increasing the significance of levels even more? It sure is.

Frost Giant Attack with shield save against 15th level fighter
ac .....avg likely damage
3 .....9.1
5@..... 2.625
5 .....10.5
7@ .....2.975
7 .....11.9
9@ .....3.325
9 .....13.3
Man oh man the high level fighter would get a huuuge advantage with shield saves. That's going to change the nature of the game a lot.

Do we want to mitigate this a little? How about shields breaking on a save roll of 1. That'll do it a bit. But man oh man that's a lot of mileage for a normal shield.

A shield save might reflect man vs man combat fairly well but it really throws things out of whack when dealing with foes that aren't men.

How about simply readjusting the armor and AC tables?
Just change what they mean a bit.

Example reformed AC/armor table
2.....Plate & Shield
4.....Mail & Shield
5.....Leather & Shield

Platemail & shield is still the bomb. Leather and mail are often really overrated and as such downgraded, historically men gave up on full suits of mail and much in the way of non-plate armor when good plate became available. The high end of the chart is kept the same. The shield is now significant but not overwhelming., it's statistically important and makes tactics much more of an issue for non-plate wearers. Some hardcases might want to adjust Ac score in adventures, other could just not worry about it.

But is that the final solution? No. how could it be. What changes are acceptable will vary with mileage from game table to game table.

Some folks favor shields being given a 2 point AC bonus and otherwise keeping things the same...but that makes plate and shield AC 1...even better then it already is.

Changing the rules changes the game. Even something like a 1 point shift in AC makes a difference. There is no one true way.


  1. And the Great Shield Debate continues. Fascinating how such a simple rule can cause so much discussion. Good post, and a good read. Thanks.