This prompted me to look at the armor class ranges of all monsters in both editions. I discovered something very interesting: there are no monsters in Holmes that have an AC lower than 2. While there are eight monsters in Cook that do, they have an average of 18 HD and only two (the dragon turtle and the 16HD elemental) have a negative AC.
Further, in Holmes, the lowest AC found in the combat tables is AC 2. This emphasizes the reality that in Holmes there are really only four armor classes:
- No armor
- Chain mail
Conceptually, understanding the shield and any magical bonus as a penalty to the attacker's roll transforms the shield and the magic bonus from being AC to being things the attacker must overcome in order to be able "to hit" the target AC.
In other words, if I were a 1st level character trying to hit an NPC wearing leather and carrying a magic +1 shield, I would normally hit on a '12' (according to Holmes); however, I would have to overcome the shield and the magic because I would be subtracting 2 from my roll. This penalty could be easily be understood and noted as a Defensive Bonus.
This implementation has a couple of consequences and a rather cool implication:
- There can be major simplification of combat tables with only four types of AC.
- There has to be a conversion of monster ACs that do not fall into these four types. For example, AC 4 becomes Chain/DB 1.
- For those that want shields to play a larger role in D&D combat, this concept of shields giving a Defensive Bonus rather than affecting the AC allows for a greater range of bonuses than the meager +1 that normal D&D allows. These bonuses could be tied to size and/or material. For example:
Small Shield +2DB
Large Shield +3DB
Tower Shield +4DB
I have yet to playtest such a system, but a imagine a major complaint might be the math. A reminder: there are very few bonuses in Holmes. Strength has no bearing on combat. Most encounters would require only the penalty due to a Defensive Bonus. For those so inclined, I imagine that implementing a house rule where rolling the exact number you need to hit (a 14 in the example above) would result in maximum damage or some kind of critical hit would give enough incentive that players would adapt very quickly.