To hit

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:

Base Value

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.

Weapons

• If not wielding a weapon, the player gets:
  • Between +0 and +Unarmed Combat
    • +4 if a troll, felid or ghoul
    • +2 if any other species
• 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) and is wielding an orcish weapon, they get +1.

Jewellery

• 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.

Skills

• Fighting gives you a bonus of +0 to +Fighting.
• Weapon skills give you a bonus of +0 to +Your Skill (if you are wielding the matching weapon).

Environmental

• When both combatants are in water and only the player is capable of swimming, the player get a +5 bonus.

Status Effects

• 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).

Shield Penalty

• The player's shield penalty is -1d(ASP) where ASP is the Adjusted Shield Penalty. It is ASP = (Shield EV penalty) - (Shields skill)/(5 + (Size factor)) as explained in the Shields page. This penalty can be removed completely with enough skill levels in Shields.

Armour Penalty

• The player's armour penalty is then calculated: -1d(ABAP) where ABAP is the Adjusted Body Armour Penalty.

ABAP = (body_armour_base_penalty + max(0, 3*body_armour_base_penalty - str)) * (45 - armour_skill)/45

Barding does not affect the to hit penalty despite having an evasion modifier.

Mutation bonus

• If the player has the Eyeballs mutation they get a +3/+5/+7 bonus.

The Roll

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.

Post-Roll

There are additional effects which can modify the to hit score AFTER it has been rolled:

• 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:
  • The Confusing Touch spell grants +0 to +(DEX-1).
  • Being in the following forms grant bonuses:
    • Statue Form: 0 to +8
    • Dragon Form: 0 to +9
    • Lich form: 0 to +9
    • Ice Form: 0 to +9
    • Spider Form: 0 to +9
    • Bat Form: 0 to +11
    • Blade Hands: 0 to +11
    • Fungus Form: 0 to +9
    • Tree Form: 0 to +9
    • Wisp Form: 0 to +9

• 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:

Base Value

The base value is 18.

Hit Dice

Monsters with the Fighter class flag get a bonus of +(2.5 * HD). Other monsters get +(1.5 * HD). Decimals are rounded down.

Situational Modifiers

• 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).