What good is a tower shield?
If a non-fighter takes the Tower Shield Proficiency, it uses a feat and gives a +4 AC for a -2 penalty to attack. Is that worth it? You can get a +2 shield bonus for free with a large shield, so you really get a +2 AC for -2 attacks for the cost of the feat. And using the shield caps your dexterity bonus to AC at +2, is freaking heavy, and imposes a hefty -10 armor check penalty. (You can reduce that to -9 with a masterwork tower shield, and to -8 with a darkwood shield.)
Bottom line, for non-fighters, is if you have the required 13 intelligence, Combat Expertise is a better choice, and is a prerequisite for other interesting feats anyway. If you do not have a high intelligence, and your dexterity is only a 14 or less anyway, then Tower Shield Proficiency may be a decent feat for you, based only on the AC bonus.
And of course, for fighters, Tower Weapon Proficiency is a free feat. That right there makes it a viable option for the lower-dexterity fighter who does not mind a "sword-and-board" strategy and can shrug off the -2 on attacks.
However, there is more to the tower shield than just the boost to armor class. You can also use the tower shield to convert one side of your spacing to a wall, offering total cover from physical attacks. Immunity to physical attacks is incredible, although you do have to give up your standard action (thus, your own attacks) to do it. Here, consider at this "grid" set up:
A B C
A hero in E, the center of the grid, sets his shield to the north, between E and B. Any foe in A, B, and C cannot make a physical attack on the hero. That's great, right? Well, maybe not ...
D E F
G H I
1) An enemy in square B takes a five foot step from B to F and then makes a full attack. That negates the use of the shield entirely! The hero does not even gain the +4 AC bonus. What good is the shield, then -- especially given that you have used your standard action for the round to set it?!
I submit that the setting of a tower shield to offer total cover is of limited utility in many cases. Sure, it is great in a narrow tunnel or against missile fire. But the ability of foes to see that it is set and then to go around it makes the tower shield the Maginot Line of D&D. If you want it for the AC boost, especially if you are a fighter, then great -- set your shield only in the rare cases when it offers an unambiguous advantage.
2) An enemy approaching from the north sees that the shield is set, and therefore approaches to the side and moves to D or F. The shield is useless.
3) An enemy approaching from the east, west, or south is inconvenienced not at all by the shield.
However, there are some things you can do to make your tower shield somewhat more useful.
First, ready your use of the tower shield. That is, use a Readied Action to trigger setting your Tower Shield for total cover. Your trigger would be something like this: "Triggered by a physical attack on me, I ready setting my shield to face the direction from which the attack comes."
The beauty of this is in not alerting your enemies that you are planning to set your shield. If an enemy approaches you, they'll use their move action getting to you, and then their attack will fail as you interpose your shield between their attack and your soft flesh. In scenario 2 above, the enemy would see the hero set her shield, and then maneuver around the shield as it came closer. A readied set cannot be detected as an enemy comes closer, and even if it does move to approach from the side, your shield still interposes -- from any direction. That counters scenario 3 above as well.
What if you are in hand-to-hand already? What if an attacker is already adjacent to the hero and is making multiple attacks? If the foe makes a full attack sequence and the first attack of the sequence is foiled in this way, then the foe CAN take a five foot step to move to another facing and take secondary attacks. It is not a perfect strategy to foil all foes, clearly. Still, depending on the map, if the foe is large or you are next to obstacles or allies, you can still make it work.
Second, be big. If you are large in size, then you cover four squares, and your set shield is two squares wide. That makes it harder for an enemy to step around you. It makes it easier to block a doorway, a hall, or stairs. Enlarge Person is your friend. You may also be able to play a large race, such as a wemic.
Third, be Maxwell's Demon. Like the tiny being that lets only certain particles through an imaginary door, you can allow your allies to move through your space -- and your set shield -- freely, while keeping enemies out. Imagine a hero with a tower shield set in a doorway. Imagine an ally with Spring Attack. The hero's pal hops into the room, attacks, and hops back out. Allies can also make ranged and spell attacks through your square, while you block all physical attacks incoming.
Fourth, take advantage of attacks of opportunity. You are using your standard action to ready the use of your shield, but you can still make attacks of opportunity, and you can still flank and threaten squares. So it behooves you, sometimes, to get into the thick of it and stand next to enemies who may provoke AoOs. You can also move around the battlefield with your shield readied to set. If you provoke an AoO, the AoO is foiled by your readied set. Against a dangerous foe with reach and no Combat Reflexes, using up the enemy's only AoO in a round may be very useful.
A few final tower shield thoughts ...
Ready, Loose, Drop! Sometimes you do not want to suffer the shield's incredible penalties -- the armor check penalty, or the 50 percent arcane spell failure. But if you are just HOLDING the shield in one hand, not using it for protection at all, then it is just a board you are holding, and it offers no penalties (beyond encumbrance).
The 3.5 D&D rules say:
Ready or Loose a Shield Strapping a shield to your arm to gain its shield bonus to your AC, or unstrapping and dropping a shield so you can use your shield hand for another purpose, requires a move action. If you have a base attack bonus of +1 or higher, you can ready or loose a shield as a free action combined with a regular move. Dropping a carried (but not worn) shield is a free action.
Pretty clearly, you can "loose" your shield (that means, take it off your arm and carry it in your hand) as a move action. And you can "ready" your shield (that means strap it to your arm for use) as a move action. You can even combine those actions with a move. So if you are an arcane caster or if you want to sneak around without penalty, you can loose your shield and do so in the same round.
The rules are a smidge more opaque in Pathfinder. The Pathfinder rules say:
Ready or Drop a Shield Strapping a shield to your arm to gain its shield bonus to your AC, or unstrapping and dropping a shield so you can use your shield hand for another purpose, requires a move action. If you have a base attack bonus of +1 or higher, you can ready or drop a shield as a free action combined with a regular move. Dropping a carried (but not worn) shield is a free action.
So what is the difference between "loose" and "drop"? What can you do under 3.5 that you can't do with Pathfinder?
If you want to take off your shield but NOT drop it on the ground, and just carry it, I imagine that's a move action too (or a free action combined with a move)? Both rules allow you to have a "carried (but not worn) shield" -- Can you unstrap and carry a shield as a move action, if you do not want to drop it, under PF? I say yes, but ask your DM.
Counters No strategy is perfect. How do you foil an enemy using a tower shield?
- Use magic. The shield does not spells or other magical attacks that target you in any way. You can also cast spells on the shield -- Warp Wood comes to mind.
- Sunder that shield. Bash it enough and it will break. Adamantine weapons are your friend here.
- Tumble through the shielder's square. Nothing says you can't.
- If you are tiny in size or smaller, you can enter the shielder's square freely without a tumble check (you do provoke AoOs doing it, however).
This screed originated as a message board thread in July and August 2011. It was posted in rough form in August 2013, and then refined and cleaned up in May 2014.
For more ideas on putting your tower shield to good use, check out this screed.