To hit (short for 'chance to hit') is the probability that an attack will hit a target. It is one of the two key factors in determining the success of an attack, the other being damage.
The to hit can be calculated for melee and ranged attacks, and is calculated differently for players and monsters.
Player To Hit (Melee)
The player's to-hit in melee is determined by the following factors:
The base of the calculation is determined by the player's dexterity AND their strength, and is somewhere around the average of the two. It is weighted toward either STR or DEX, depending on the strength weight of the weapon. Weapons with a low strength weight will benefit more from DEX for its to hit value, while weapons with a high strength weighting rely more on STR. A half-handed weapon will rely even further on STR if used without a shield. Unarmed attacks are weighted slightly toward DEX. For the sake of completeness, the base to-hit is something like
15 + (Weighted Average of STR & DEX)
with the weighting determined by the weapon's strength weight.
- If not wielding a weapon, the player gets:
- If wielding a weapon, the player gets that weapon's intrinsic accuracy, plus any accuracy enchantment (the first plus on the weapon).
- If the player is elven and is wielding an elven weapon, they get +1d2.
- If the player is an orcish worshipper of Beogh (and not under penance), they get +1.
- If the player is wearing an amulet of inaccuracy, they get a random penalty ranging from -0 to -5.
- If the player is wearing a ring of slaying, they get the ring's hit bonus/penalty.
- Fighting gives you a bonus of +1 to +Fighting.
- Weapon skills give you a bonus of +1 to +Your Skill (if you are wielding the matching weapon).
- When both combatants are in water and only the player is capable of swimming, the player get a +5 bonus.
- If the player is starving, they get a -3 penalty.
- If the player is invisible but cannot see invisible, they get a -5 penalty (because they cannot see what they are doing).
- The player's armour penalty is then calculated:
- If the player is wearing a normal sized shield, they have a (6-Shields skill)/7 chance of incurring a -1 armour penalty (a player with Shields skill of 6+ will not have this penalty).
- If the player is wearing a large shield:
- An evasion penalty is now calculated, using the evasion modifier of the currently worn body armour as a base. This only applies to body armour, such as leather armour or mail: cloaks, helmets, gloves and so forth do not have an evasion modifier. Barding does not affect the to hit penalty despite having an evasion modifier.
- If the player is a merfolk and is swimming in deep water, the evasion penalty of their armour is doubled.
- The player now has an evasion penalty/armour skill chance that the some or all of the evasion penalty will be added to their armour penalty.
- If the player is wielding a weapon, the armour penalty will then be multiplied by 2 or 3 (50% chance of either). Unarmed fighters do not get this penalty.
- The armour penalty is added to the player's chance to hit.
This completes the to hit calculation. The value is now 'rolled' (ie. a number from 0 to to hit-1 is randomly generated). If this number exceeds the evasion value of the monster they are attacking, they hit lands.
There are additional effects which can modify the to hit score AFTER it has been rolled:
- Wielding a non-cursed, half-handed weapon without a shield gives you +0 to +2.
- If the player is bonded to their weapon with the Sure Blade spell, they get +(5 + remaining duration of Sure Blade (MAX: +15)).
- If the player is not wielding a weapon:
- Attacking a target under the effects of the Corona spell grants +2 to +9.
- Attacking an invisible monster without being able to see invisible gives you -6.
Monster To Hit (Melee)
A monster's to hit is calculated as follows:
The base value is 18.
Monsters with the Fighter class flag get a bonus of +(2.5 * HD). Other monsters get +(1.5 * HD). Decimals are rounded down.
- An aquatic monster "using the terrain to its advantage" gets +5.
- A monster wielding a weapon receives that weapon's inherent and magical to hit modifiers.
- A confused monster gets -5.
- A monster attacking a backlit defender gets +2 to +9.
- A monster attacking an invisible target suffers a 35% penalty to its to hit number.
Monster To Hit (Ranged)
Ranged attacks ("beams", to use the game's internal terminology) have a to hit number, just like melee attacks do. This is modified as follows:
- If you are invisible and the attacker can't see invisible, the to hit number is halved.
- If you have Deflect Missiles running, the to hit number is reduced to a random number between 0 and 2/3 of its value.
- If you don't have Deflect Missiles running, but do have Repel Missiles running or the Repulsion Field mutation at level 3, the to hit number is reduced by a random number between 0 and 1/2 of its value (rounded down).