Eldritch Tamers Go!
Pokemon Rules (for non-pokemon players)
While much of the underlying math of the Pokemon games is hidden from the players by the UI, and (in this game) will be abstracted away from the players by the GM, it is helpful for intermediate and advanced players to understand exactly what that math is to better plan their strategies. This page will attempt to explain both the core Pokemon rules, and how they are translated into a table-top format (which mostly boils down to “the DM’s got some awesomely complicated spreadsheets” and “The Players roll a d20”).
- Stat Calculation
- Type Matchups
- Move Characteristics
- Accuracy Checks
- Damage Calculations
- Critical Hits
- Secondary Effects
- Catch Probability
- Status Conditions
- Random Encounters
Each Pokemon is defined by 6 statistics: Hit Points (which should be self-explanatory to any player of RPGs), Attack (which determines the damage of physical attacks), Defense (which reduces the damage of physical attacks), Special Attack (which determines the damage of special attacks), Special Defense (which reduces the damage of special attacks), and Speed (which determines which pokemon acts first in a combat round).
A pokemon’s statistics at a given level are determined by the following factors:
- Base Stats: Determined by the pokemon’s species, this has the greatest influence over the pokemon’s statistics. Disregarding all other factors below, a pokemon’s total stat value at level 100 will be equal to 5 + 2x it’s base stat. See the List of Pokemon Base Stats for details.
- Nature: A pokemon’s nature represents its dominant personality trait. The pokemon’s nature will increase a single stat by 10%, and lower another stat by 10%. Natures never affect a pokemon’s hit points. There are 24 possible natures, and a caught pokemon’s nature will be randomly determined by a d24 roll. See the List of Natures for details.
- Individual Values (IVs): Individual Values cause two Pokémon of the same species to have different stats. Within the core Pokemon games, each statistic has an IV represented by a range of 0 to 31. To simplify random generation of IVs, wild pokemon caught in this game will have a IVs calculated by a d30 roll (giving a range from 1-30). 1 point of IV represents a 1-point increase to the pokemon’s stat value at the maximum level of 100.
- Effort Values (EVs): Effort values are what cause a trained Pokémon to have higher stats than an untrained counterpart of the same level. Each time you defeat another pokemon in battle, you will gain 1-3 points of EV to a given statistic (generally the highest base stat of the defeated species). Every 4 points of earned EVs grants +1 to the pokemon’s total stat value at level 100. A pokemon can earn a maximum of 510 EVs, and no more than 252 EVs in a single stat.
- Level: When a Pokémon grows a level, its stats will increase. For each level gained (ignoring Nature), stats will increase by 1/50 the base stat value, and 1/100 the combined IVs and EVs. This means that it is impossible, through leveling up, for a Pokémon to ever lose points in a stat unless it evolves into a Pokémon with a lower base stat value for that specific stat.
Calculations: Stats are calculated using the above factors according to the formula below. The stat is rounded down if the result is a decimal. The stat is also rounded down before the Nature multiplier, if any, is applied.
HP = 10 + Level + ((2xBase + IV + (EV/4)) x Level/100)
Stat = (5 + ((2xBase + IV + (EV/4)) x Level/100)) x Nature
Temporary Stat Modifiers:
In combat, numerous moves, items, and abilities can temporarily raise or lower a pokemon’s statistics. In battle, statistics raise or lower by stages, to a maximum of 6 stages. Depending on the number of stages of increases/decrease, the stats are modified as follows:
Shiny pokemon are pokemon with a different coloration from the norm for their species. Like albinism in real-world creatures, these mutations occur very rarely. Shininess is desirable for its rareness and aesthetic reasons, but has no direct mechanical impact on the games.
In the core games the chance of a pokemon being shiny is determined by a variety of methods. In Gen III and later, shininess is determined by RNG with a probability of 1 in 8192 (or 0.012%). In Gen I and Gen II, shininess is determined by the IVs of the pokemon — since we already have a way of determining IVs, this is the method we will be using.
A pokemon will be shiny if its IVs match the following: Defense, Special Attack, Special Defense, and Speed IVs must be exactly 20, Attack IVs must be 4, 6, 12, 14, 20, 22, 28 or 30, and Hit Points IVs must be either 8 or 16. Thus all Shiny pokémon are generally above average in terms of IVs, but only slightly.
Types are properties for Pokémon and their moves. There are 18 known types. A Pokémon may have either one or two types: For instance, Charmander is a Fire type, while Bulbasaur is both a Grass type and a Poison type. With the current 18-type system, there are 324 possible unique combinations.
A move has exactly one type. The type of a damaging move typically defines which types of Pokémon it is super effective against, which types of Pokémon it is not very effective against, and which types of Pokémon it is completely ineffective against.
Type effectiveness greatly influences how much damage moves deal:
- If the type of a move is super effective against a type of its target, the damage done is double (2x) the normal amount.
- If the type of a move is not very effective against a type of its target, the damage done is half (½x) the normal amount.
- If the type of a move is not effective against a type of its target, the target is completely immune to it, and the move will deal no damage (0x).
For targets that have two types, overall type effectiveness is the combined effectiveness against each of its types:
- If the type of a move is super effective against both of the opponent’s types (such as Dig, a Ground-type move, used against an Aggron, a Steel/Rock Pokémon), then the move does 4 times the damage;
- If the type of a move is not very effective against both of the opponent’s types (such as Wake-Up Slap, a Fighting-type move, used against a Sigilyph, a Psychic/Flying Pokémon), then the move only does ¼ of the damage;
- If the type of a move is super effective against one of the opponent’s types but not very effective against the other (such as Razor Leaf, a Grass-type move, used against a Gyarados, a Water/Flying Pokémon), then the move deals normal damage.
- If the type of move is completely ineffective against one of the opponent’s types, then the move does no damage, even if the opponent has a second type that would be vulnerable to it (as in Thunderbolt, an Electric-type move, used against a Quagsire, a Water/Ground Pokémon).
Status moves typically do not employ type effectiveness; however, some types grant immunity to specific status conditions: Fire-type pokemon are immune to the Burn condition; Ice-type pokemon are immune to Freeze; Electric-type pokemon are immune to Paralysis; and Poison-type and Steel-type pokemon are immune to Poison.
Pokemon learn a variety of moves (sometimes referred to as “Attacks” or “Techniques”).
A Pokémon can only know four moves at a time, which are drawn from a pool of 746 total moves. However, no single Pokémon has access to all moves; all 807 Pokémon have a given movelist with a limited amount of moves that relate to the type and concept of the species. Sometimes, Pokémon’s movelists vary between evolutionary relatives. This often is tied to a secondary type gained or lost on evolution, but can also provide incentive to prevent a Pokémon’s evolution to a higher stage.
Characteristics of Moves:
Pokémon are limited in the way that they may use their moves in battle. The number of times they can use each move is restricted by the move’s Power Points. Power Points vary from move to move, but typically stronger moves have fewer Power Points than weaker moves. The only move that is not affected by Power Points is Struggle.
The strength of a move is measured by its Power, and other factors such as Accuracy affect whether it does damage or not. Some moves have additional effects that cause status conditions on the target, and some do no damage at all. Moves that do not explicitly cause harm to their target are known as Status moves; the remaining moves are divided into Physical and Special moves depending on the individual move’s characteristics; the category of the move determines whether the move’s power relies on the Attack or Special Attack stat. Most moves can target only one adjacent Pokémon, but some moves instead can target the user, more than one Pokémon, or non-adjacent Pokémon.
Like Pokemon, each move has an associated type, which determines the moves effectiveness against pokemon of opposing types. A pokemon using a move where the move’s type matches one of its types gains a 50% increase to the damage dealt.
Here is an example move-set, showing the relevant characteristics:
|Move||Type||Category||Power||Accuracy||Special Effects||Power Points|
|Shadow Bone||Ghost||Physical||85||100%||20% chance to lower Defense 1 stage.||10|
|Screech||Normal||Status||—||85%||Lower Defense 2 stages.||40|
|Uproar||Normal||Special||90||100%||Attacks 3 turns. Sleep does not work.||10|
The number of times they can use each move is restricted by the move’s Power Points (PP). Power Points vary from move to move. Each time a move is used, its PP are decreased by 1. A move with 0 remaining PP cannot be used again until the PP are restored.
Expended Power Points can be restored by items (such as an Ether), by certain moves (such as Lunar Dance), by healing at a Pokemon Center, or by a “Long Rest” (8+ hours of uninterrupted sleep in its Pokeball).
A Pokemon with 0 PP in all of its moves cannot use any attacks, but may “Struggle”. Struggling counts as an attack known by all pokemon, it has no limit to its use, but can only be used when the pokemon has 0 PP. As an attack, Struggle is type-less (meaning that no pokemon has resistance to it, and no pokemon gains a STAB bonus when using it), and has the following characteristics:
|Move||Type||Category||Power||Accuracy||Special Effects||Power Points|
|Struggle||N/A||Physical||50||100%||User takes recoil damage equal to 1/4 its maximum hit points.||—|
There are four main methods of acquiring moves on a Pokémon: by leveling up, by use of Technical Machines, moves learned through breeding, and moves taught by a non-player character Move Tutor.
A Pokémon can only know four moves at a time. In order to learn new moves once four have been learned, it must forget one old move for every new move.
In the core Pokémon games, there are two other statistics that can be adjusted in battle: Accuracy and Evasion. At the start of a battle, both of these statistics begin at 100%. The chance of any attack hitting is determined by the equation, where A is the base accuracy of the Move being used:
P = A x (Accuracy / Evasion)
If P is greater than 1, the move being used will always connect.
Certain moves can raise or lower these values, with the effects of such changes lasting until the end of the current encounter. Accuracy and Evasion can be raised or lowered a maximum of 6 stages, with the corresponding effects to your chance to hit (as calculated by the Equation above).
Even with handy spreadsheets, this math gets waaay too cumbersome for a tabletop game…
For the the Tabletop version of the game, this is simplified somewhat. An attack roll will be made using an unmodified d20. This is rolled against a target DC equal to (20 – (20*A)). Thus a pokemon using the move Zap Cannon (which has a base accuracy of 50%) would have to roll a 10 or higher on a d20 to hit the target.
A roll of a ‘Natural 1’ on the d20 always misses (regardless of the attack’s base accuracy). A roll of a ‘Natural 20’ similarly always hits.
Rather than tracking changes to the Accuracy or Evasion stats, each stage of change imposes either Advantage (roll multiple dice and take the highest result) or Disadvantage (roll multiple dice and take the lowest result).
Multiple changes to Accuracy or Evasion, stack to a maximum of 10 Dice1 (taking either the highest or lowest die, depending on whether the net accuracy would be improved or diminished). Thus if a pokemon had +3 Accuracy and was striking against a pokemon with +1 Evasion would have a net +2 Advantage —
rolling 3 dice and taking the best result. Likewise, a pokemon with -3 Accuracy would roll 4 dice and take the lowest result.
Note that the advantaged or disadvantaged roll is still made against the same target DC, so an attack with 100% accuracy would still only miss on a ‘1’. However, at 5 or more stages of disadvantage, the chance of rolling a ‘1’ is very high. This also means that imposing disadvantage by increasing evasion or lowering accuracy also decreases the overall damage of an attack, the chance of Critical Hits, and the likelihood of secondary effects from attacks (since all are determined by the same roll).
Changes to Accuracy apply to Advantage or Disadvantage on all attacks made by the Pokémon, and remain in effect until such time as the pokémon switches our and/or returns to its pokéball. Similarly, changes to Evasion apply Advantage or Disadvantage on all attacks made against the Pokémon, and remain in effect until such time as the pokémon switches our and/or returns to its pokéball.
1 Note: The changes to probability granted by this rolling method are roughly equivalent to the change in probability caused by the Stage increases or decreases above. Beyond 10 dice, the change is negligible (less than 0.02% per added die). Also, more than ten 20-sided-dice are just hard to hold.
Optional Rule: Dodging:
One aspect of the pokemon stories that is not captured by the core mechanics of the pokemon video games is the idea of dodging attacks. Throughout the Pokémon Anime and Manga, Ash or Red, and their companions and opponents are constantly telling the pokémon to “Dodge it!” in response to an attack.
Any Pokémon can choose to “Dodge” in place of using a move/attack in a given turn. Using the Dodge action imposes 1 level of Disadvantage on the attack roll of the opposing pokémon (this stacks with other changes to Accuracy/Evasion as above) — decreasing not only the chance of being hit, but also the chance of critical hits and secondary effects, and resulting in a small decrease to damage if the pokémon is hit.
The accuracy reduction from Dodging applies only to attacks made during the turn in which the Dodge action is taken.
Attack Rolls and Damage:
Except for moves that deal direct, fixed damage (such as Dragon Rage), the damage dealt when a Pokémon uses a damaging move depends on its level, its effective Attack or Special Attack stat, the opponent’s effective Defense or Special Defense stat, and the move’s effective power. In addition, various factors of damage modification may also affect the damage dealt.
More precisely, damage is calculated as:
- Level is the level of the attacking Pokémon.
- A is the effective Attack stat of the attacking Pokémon if the used move is a physical move, or the effective Special Attack stat of the attacking Pokémon if the used move is a special move.
- D is the effective Defense stat of the target if the used move is a physical move or a special move that uses the target’s Defense stat, or the effective Special Defense of the target if the used move is an other special move.
- Power is the effective power of the used move.
Numerous factors can modify this base damage calculation:
- If the move affects multiple targets then the damage is 0.75x the base damage.
- Weather effects can either increase or decrease the damage (i.e. during Rain a Water-type move deals 1.5x damage, while Fire-type moves deal 0.5x damage).
- Possessing the Gym Badge of the corresponding type increases the damage of moves of that type by 10% (1.1x).
- STAB (Same Type Attack Bonus) is equal to 1.5x if the move’s type matches any of the user’s types.
- Type effectiveness can be 0x (ineffective); 0.25x, 0.5x (not very effective); 1x (normally effective); 2x or 4x (super effective) depending on both the move’s and target’s types.
Attack Rolls and Critical Hits:
In addition to determining whether or not an attack hits (see Accuracy above), the 1d20 roll also factors into the attack’s damage. In the core games, damage is multiplied by a random factor between 0.85 and 1.00 (inclusive), to simplify this randomization, the damage of an attack is multiplied by an amount equal to (1d20+80)/100, using the same roll as was used for the Accuracy check.
A roll of 20 on the attack roll is a Critical Hit. A Critical Hit deals double (2x) the attack’s maximum damage.
Some moves (such as Slash) have an increased chance of inflicting a Critical Hit. Other moves (such as Focus Energy), items (such as Dire Hit), and Abilities (such as Super Luck) can further increase the chance of landing a Critical Hit.
Each such increase reduces the necessary roll to score a Critical Hit by 1. Thus an Absol with the ability Super Luck, who is holding a Scope Lens, and using the move Night Slash would score a Critical Hit on any roll of 17 or higher.
Attack Rolls and Secondary Effects:
Numerous pokemon moves have secondary effects in addition to dealing damage to the target. They may increase or decrease the statistics of the attacker or defender, or inflict status conditions such as poisoning, confusion, or flinching.
In the core games, the chance of secondary effects are represented by a percentage (typically a multiple of 10%). For the purposes of attacks in this game, this chance will be rolled into the d20 attack roll, just as are accuracy, damage, and critical hits. Secondary effects will occur if a particular target is hit on the d20 roll, determined by the move’s % chance of having its additional effects.
|Secondary Effect Chance||d20 Target|
Each species of Pokémon has a Catch Rate that applies to all its members, ranging from 3 to 255. Higher catch rates mean that the Pokémon is easier to catch, up to a maximum of 255.
When a Poké Ball is thrown at a wild Pokémon, the chance of catching it is determined by this catch rate, along with other factors: The health of the Pokémon (relative to its full health), the type of Poké Ball used, any status condition of the wild Pokémon, and whether or not the trainer has an appropriate gym badge. This catch chance is determined according to the following formula:
The various Poké Balls typically have a catch chance modifier between 1x and 8×. Status conditions provide either a 2x (Sleep or Freeze) or 1.5x (Paralyze, Poison, or Burn) modifier.
For a Pokémon at 0 HP, the maximum catch chance is rate × ball bonus × status. For a Pokémon with full health and no status condition, and with a neutral ball used, the minimum catch chance is rate / 3.
This formula gives a modified catch rate represented as an interger between 1 and 255. To determine the actual chance of catching the pokemon, this modified catch rate is divided by 255 to give us a percentage chance of capture. A trainer possessing a Gym Badges corresponding to the pokemon’s type gains a flat 10% increase to this calculated percentage (to a maximum of 100%).
For this version of the game, the % capture chance is multiplied by 20 (and rounded to the nearest whole number) to give us the target number for a d20 roll, using the formula T = 20 – (20*catch %). When a Poké Ball is thrown at a wild pokemon, the player rolls 1d20 which is compared against this calculated target value.
Regardless of the calculated catch chance, a roll of 20 is always a successful catch (sometimes referred to as a “Critical Catch”).
Status conditions, also referred to as status problems or status ailments, affect a Pokémon’s ability to battle. There are three kinds of status. The first are non-volatile, the second are volatile, and the third lasts while a Pokémon is in battle.
A non-volatile status condition is a status condition that remains outside of battle and after being returned to its pokeball and switched out. A Pokémon can only be afflicted by one non-volatile status condition at a time. They can be cured by healing at a Pokémon Center, specific curative items, and other ways. There are five Non-volatile status conditions:
- Burn: The Burn condition inflicts damage to the pokemon each round equal to 1/16 it’s maximum hit points. In addition, while afflicted with Burn, the pokemon deals half damage (0.5x) with all physical attacks. Fire-type Pokémon and Pokémon with the Water Veil or Water Bubble Ability cannot normally be burned.
- Freeze: The Freeze condition causes a Pokemon to become encased in ice and unable to take any actions. A frozen Pokémon can still use the moves Fusion Flare, Flame Wheel, Sacred Fire, Flare Blitz, Scald, and Steam Eruption while frozen; these moves will thaw the user and be executed normally. A frozen pokemon that is hit with a move capable of inflicting Burn will be immediately cured. A frozen pokemon has a 20% of thawing out on their own at the end of each round. Ice-type Pokémon and Pokémon with the Magma Armor Ability cannot normally be frozen. Pokémon cannot be frozen in harsh sunlight.
- Paralysis: The Paralyzed condition reduced the Speed stat of the affected pokemon by 50%. In addition, a paralyzed pokemon has a 1-in-4 chance each round of being unable to take any actions (being “fully paralyzed”) during that round only. Electric-type Pokémon and pokemon with the Limber Ability cannot be paralyzed.
- Poison: The Poison condition inflicts damage to the pokemon each round equal to 1/8 it’s maximum hit points. A Pokémon with the Poison Heal Ability will restore an equivalent amount of HP instead of taking damage. Poison-type Pokémon, Steel-type Pokémon, and Pokémon with the Immunity Ability cannot be normally poisoned.
- Badly Poisoned: Certain moves (Poison Fang, Toxic, and Toxic Spikes) inflict a more severe form of poisoning, referred to as “Badly Poisoned”. A badly poisoned pokemon suffers escalating damage each round, This begins at 1/16 of the Pokémon’s maximum HP the first round, with the damage inflicted increasing by 1/16 each turn thereafter (2/16 on the second turn, 3/16 on the third turn, etc.).
- Sleep: The Sleep condition causes a Pokémon to be unable to take any actions (except using the moves Snore and Sleep Talk). Sleep lasts for 1d6 rounds, unless self-inflicted via the move Rest, in which case it lasts for exactly 2 rounds. In addition to moves that cause sleep, a disobedient Pokémon may also nap during battle. Pokémon with the Vital Spirit or Insomnia Ability cannot normally be put to sleep.
A volatile status is a status condition that is inflicted by a move or Ability from another Pokémon and will wear off when a Pokémon is switched out of battle or when a battle is over. Many volatile status conditions will also wear off after a number of turns have passed. A Pokémon can be affected by multiple volatile status conditions at a time. There are a large number of volatile status conditions:
- Bound: When a Pokémon is hit by a binding move (Magma Storm, Sand Tomb, Whirlpool, Wrap, Bind, Clamp, Infestation, or Fire Spin), it becomes bound. A bound pokemon is unable to return to its pokeball or switch out, and suffers damage equal to 1/16 of the afflicted Pokémon’s maximum HP at the end of each round. If the Pokémon that used the binding move held a Binding Band, the damage is instead equal to 1/8 of the afflicted Pokémon’s maximum HP. Binding effects last for 1d4+1 rounds (5 turns if the user of the binding move held a Grip Claw). A Pokémon can only be bound by one binding move at a time. Ghost-type Pokémon can switch out and flee even if they are trapped by a binding move.
- Trapped: A Trapped Pokémon is unable to switch out or flee as long as the Pokémon that trapped it is on the field. The moves Mean Look, Spider Web, Block, Shadow Hold, Spirit Shackle, and Anchor Shot can inflict the Trapped condition. A Pokémon that is Trapped can still switch out if it is holding a Shed Shell; uses U-turn, Volt Switch, or Baton Pass; or is hit by Whirlwind, Roar, Dragon Tail, or Circle Throw. Ghost-type Pokémon are immune to the Trapped condition.
- Confused: The confused condition causes a Pokémon to sometimes hurt itself in its confusion instead of executing a selected move. There is a 2-in-6 chance each round that the Pokemon will damage itself. The damage is done as if the Pokémon attacked itself with a 40-power typeless physical attack (without the possibility of a critical hit). Confusion wears off after 1-4 attacking turns. This means that turns recharging, such as after using Hyper Beam, and turns unable to attack, such as from paralysis, will not lower the remaining number of turns of confusion. Multi-turn attacks such as Fly and Dive require confusion to be checked both turns, further reducing the chance of a successful attack. Pokémon with the Own Tempo Ability are immune to being confused.
- Curse: If a Ghost-type Pokémon uses Curse, its target will be afflicted by the Cursed condition. A cursed Pokémon takes damage equal to ¼ of its maximum HP every turn. The cursed condition remains as long as the afflicted Pokémon is on the field. If a cursed Pokémon uses Baton Pass, the cursed condition is passed to its replacement.
- Flinch: The flinch status is a one-turn status that prevents a Pokémon from taking any actions. A Pokémon can only flinch if it is hit by another Pokémon’s move before using its move. Pokémon with the Inner Focus Ability are immune to flinching. Pokémon with Steadfast still flinch, but gain Speed each time they do so.
- Heal Block: A Pokémon affected by Heal Block is prevented from it’s restoring Hit Points by any means for five turns.
- Infatuation: A Pokémon that is infatuated has a 50% chance per round of being unable to take any actions, even against Pokémon other than the one it is infatuated with. Pokémon with the Oblivious Ability are immune to infatuation. Infatuation will end as soon as either the affected Pokémon or the Pokémon it is attracted to is removed from the battle.
Numerous other volatile status effects exist which can be inflicted by various moves, including: Embargo, Encore, Leech Seed, Nightmare, Taunt, Telekinesis, Torment, and others. Because these effects are typically unique to a single move, they will not be detailed here.