Modifiers to the Attack Roll
The example above is quite simple. In a typical AD&D game combat situation,
THAC0 is modified by weapon bonuses, Strength bonuses, and the like. Figure
Strength weapon modifiers, subtract the total from the base THAC0, and record this
modified THAC0 for each weapon on the character sheet. Subtract the target's
Armor Class from this modified THAC0 when determining the number needed to attack
Here's the same example, with some common modifiers thrown in:
Rath is still a 7th-level fighter. He has a Strength of 18/80 (which gives him
a +2 bonus to his attack roll). He fights with a long sword +1. His THACO is
14, modified to 12 by his Strength and to 11 by his weapon. If attacking the orc
from the earlier example, Rath would have to roll a 5 or higher on 1d20 in
order to hit (11-6=5). Again, Table 44 in the Player's Handbook
would tell him how much damage he inflicts with his weapon (this information
should also be written on his character sheet).
In combat, many factors can modify the number a character needs for a
successful hit. These variables are reflected in modifiers to the to-hit number or to
the attack roll.
Strength Modifiers: A character's Strength can modify the die roll, altering both the chance to
hit and the damage caused. This modifier is always applied to melees and attacks
with hurled missile weapons (a spear or an axe).
A positive Strength modifier can be applied to bows if the character has a
special bow made for him, designed to take advantage of his high Strength.
Characters with Strength penalties always suffer them when using a bow. They simply
are not able to draw back the bowstring far enough. Characters never have
Strength modifiers when using crossbows--the power of the shot is imparted by a
Magical Items: The magical properties of a weapon can also modify combat. Items that impart a
bonus to the attack roll or Armor Class are identified by a plus sign. For
example, a sword +1 improves a character's chance to hit by one. A suit of chain mail +1 improves the Armor Class of the character by one (which means you subtract
one from the character's AC, changing an AC of 5 to an AC of 4, for example).
Cursed items have a negative modifier (a penalty), resulting in a subtraction from
the attack roll or an addition to Armor Class.
There is no limit to the number of modifiers that can be applied to a single
die roll. Nor is there a limit to the positive or negative number (the total of
all modifiers) that can be applied to a die roll.
Table 35 lists some standard combat modifiers. Positive numbers are bonuses for the
attacker; negative numbers are penalties.
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