I've been looking at using this rule, among others, in the games I'm setting up.
To me, the changes in damage values make a lot of sense in the grand scheme of things. Some weapons are just better suited for fighting against larger creatures.
Below are some tables I've compiled listing the average damage values for all the weapons listed on pg. 15 and the point changes in the average damage when fighting against large opponents.
Weapons with Damage LossWeapon | Damage vs. Man-Sized | Damage vs. Large | Point Difference |
Dagger | 2.5 | 2 | -0.5 |
Hand Axe | 3.5 | 2.5 | -1 |
Mace, Military Pick, Dwarven Hammer | 3.5 | 2.5 | -1 |
Morning Star | 4.5 | 3.5 | -1 |
Weapon with Damage IncreaseWeapon | Damage vs. Man-Sized | Damage vs. Large | Point Difference |
Sword | 4.5 | 6.5 | +2 |
Spear, Thrown/thrust | 3.5 | 4.5 | +1 |
Spear, thrust vs. charge | 4.5 | 7 | +2.5 |
Spear, set vs. charge | 5.5 | 9 | +3.5 |
Pole Arms | 4.5 | 6.5 | +2 |
Halberd | 5.5 | 7 | +1.5 |
2-Handed Sword | 5.5 | 10.5 | +5 |
Mounted Lance | 4.5 | 13 | +8.5 |
Pike | 4.5 | 6.5 | +2 |
Sling stone | 2.5 | 3.5 | +1 |
Weapons with No Change in DamageWeapon | Damage Range | Average Damage |
Battle Axe | 1-8 | 4.5 |
Flail | 1-8 | 4.5 |
Arrow or Quarrel | 1-6 | 3.5 |
Looking at the tables, I came to the assessment that the change in damage value seems to be based various factors: If the weapon deals blunt damage, the value is based on the possible momentum that can be generated by the wielder, while bladed/pointed weapons are based on the ammount of possible penetration based on a thrust with the weapon.
My assessments/thoughts on some of the individual weapons in the table.
Dagger: Against a large creature, a dagger doesn't fair well. The blade can penetrate the skin or hide to deal damage, but doesn't penetrate very deep. Medieval daggers ranged in size from 6 to 20 inches, as compared to the roughly 4-foot-long Sword: the blade could only penetrate as deeply as the crossguard would let it.
Hand Axe: The Hand Axe also has a stout blade, and thus doesn't penetrate deeply either. It can only sink itself up to the haft.
Mace, Military Pick, Dwarven Hammer, and Morning Star: The military pick runs into the same problems as both the Dagger and Hand Axe: the pointed pick-head can only dig as deep as the haft lets it. The damage potential of the Mace and Dwarven Hammer are limited by the strength of the wielder, thus the new rules for strength adjustment to damage found earlier in the
Greyhawk rules. Also, though the impact of the Mace and Dwarven Hammer are centered on one spot, the majority of the injury from a blunt weapon actually comes from the vibrations that the impact sends through the body, which can fracture bones, rupture organs, and cause internal bleeding. Large creatures like giants and dragons have a larger mass and surface area for the vibrations of the blunt-force trauma to travel, making the damage the residual effects of the damage near-negligible. The Morning Star suffers the same as the Mace and Dwarven Hammer in regards to larger opponents. However, since Morning Stars normally spiked, this is reflected by the increased damage range against man-sized opponents (whihc translates to larger opponents).
Sword: Though the Sword is nearly the same as the Dagger in form and function (cutting and thrusting), the Sword has the advantage of having a longer blade, allowing for deeper penetration through skin and hide, thus more damage potential against large opponents.
Halberd: The Halberd combines the penetrative ability of spears and pikes while also having the versatility of a bladed, axe-like head. The combination of usages seems to me to be the cause of the damage increase against larger opponents: more options of how to damage equals more ways to take it down.
2-Handed Sword: These were mainly used to unhorse knights on the battlefield (but who really does that in D&D games?). The extended blade length allows the wielder to possibly strike at more vital spots on larger opponents, as well as the capability of gaining more momentum on a cutting swing and deeper penetration with a thrust.
Sling stone: The simplest explanation as to why slings gains in increase in damage against large opponents would be the Biblical story of David and Goliath, but I see more. The sling stone is essentially a bullet. If a bullet, being blunt, can penetrate objects of various resistance, slings can do so as well. Scientific tests have shown that a sling stone can travel on average 30 meters per second (~67 mph). A rock or lead bullet traveling at this rate that doesn't penetrate skin or hide can still fracture bones and can cause massive internal trauma.
Battle Axe: The Battle Axe is one of three weapons that don't have a damage increase against large opponents. When I see the word Battle Axe, I see the Dane axe (or English long axe) being used rather than saomething akin to the francisca (my default image of a Hand Axe). The Battle axe has no adjustment due to balancing factors: the wider and possibly longer cutting edge of the axe-head counteracts the width of the head iself, providing more cutting surface as opposed to deeper penetration. In addition, having a longer haft allows for a smaller loss of power into the cutting edge.
Flail: As opposed to the straight-hafted Morning Star, the Flail has the benefit of increased momentum from the free-swinging flail head (thus, no decrease in damage while still using the same basic damage range).
Arrow or Quarrel: These projectiles fly at set velocities, and thus really have no variance in penetrative potential.
All the above said, story and scenario should
always trump rules: It if makes sense that a character wants to slit the throat of a sleeping 30-HP fighter (and manages to do so undetected), let him do it without rolling for damage. Even as a DM, I'd hate to see the scenario play out like this:
Player: I'll sneak up on him and slit his throat while he sleeps.
(Sneak attempt succeeds.)
Me: Okay, you knife him. Roll damage for your dagger.
(Roll)
Player: 1...
*all facepalm*