Pokémon Ruby/Sapphire - Various Notes

These are various notes for the Pokémon versions Ruby, Sapphire, Emerald, FireRed, and LeafGreen.



Personality ID

Each Pokémon comes with a 32 bit identifier, generated at random, which determines significant information about the uniqueness of the Pokémon. (This ID is sometimes called "Personality Value" or "Personality ID". It is not to be confused with a Pokémon's Trainer ID.)

Nature

The remainder of a Pokémon's personality ID divided by 25 identifies the nature of that Pokémon. Most natures raise one stat by 10% and lower another stat by 10%. Most natures also make Pokémon like or dislike certain kinds of food. Shown here are the food preferences of Pokémon with those natures (what Pokéblocks or Poffins they like), and the stats to increase and decrease.

Hex	Nature	Like	Dislike	Stat increase	Stat decrease
00	Hardy	----	----	----	----
01	Lonely	Spicy	Sour	+Attack	-Defense
02	Brave	Spicy	Sweet	+Attack	-Speed
03	Adamant	Spicy	Dry	+Attack	-Special Attack
04	Naughty	Spicy	Bitter	+Attack	-Special Defense
05	Bold	Sour	Spicy	+Defense	-Attack
06	Docile	----	----	----	----
07	Relaxed	Sour	Sweet	+Defense	-Speed
08	Impish	Sour	Dry	+Defense	-Special Attack
09	Lax	Sour	Bitter	+Defense	-Special Defense
0A	Timid	Sweet	Spicy	+Speed	-Attack
0B	Hasty	Sweet	Sour	+Speed	-Defense
0C	Serious	----	----	----	----
0D	Jolly	Sweet	Dry	+Speed	-Special Attack
0E	Naive	Sweet	Bitter	+Speed	-Special Defense
0F	Modest	Dry	Spicy	+Special Attack	-Attack
10	Mild	Dry	Sour	+Special Attack	-Defense
11	Quiet	Dry	Sweet	+Special Attack	-Speed
12	Bashful	----	----	----	----
13	Rash	Dry	Bitter	+Special Attack	-Special Defense
14	Calm	Bitter	Spicy	+Special Defense	-Attack
15	Gentle	Bitter	Sour	+Special Defense	-Defense
16	Sassy	Bitter	Sweet	+Special Defense	-Speed
17	Careful	Bitter	Dry	+Special Defense	-Special Attack
18	Quirky	----	----	----	----

Note that preference to certain foods affects a Pokémon's stats. For instance, if a Pokémon's nature indicates that it likes spicy food, its Attack will increase, but if the nature indicates that it dislikes spicy food, its Attack will decrease.

Ability

A Pokémon's initial ability is determined by whether the personality ID is odd or even. If it's even, it has the first ability, and if odd, the second ability.

If a Pokémon is migrated from a GBA game to a generation 4 game, it keeps its ability, even if its personality ID states that it would have a different ability. (Also, a migrated Pokémon is not considered to be caught with a Park Ball.) If a Pokémon evolves in a generation 4 game, it receives the ability conforming to its personality ID.

Gender

The remainder of a Pokémon's personality ID divided by 256 contains that Pokémon's gender value. Each Pokémon species has one of the following seven gender rates.

• 12.5% female - If gender value is 0 through 30, the Pokémon is female; otherwise, male.
• 25% female - If gender value is 0 through 63, the Pokémon is female; otherwise, male.
• 50% female - If gender value is 0 through 126, the Pokémon is female; otherwise, male.
• 75% female - If gender value is 0 through 190, the Pokémon is female; otherwise, male.
• Always male - Always male regardless of gender value.
• Always female - Always female regardless of gender value.
• Genderless - Unknown gender, regardless of gender value.

Unown form

To find the Unown form, the game does the following:

1. Set Y to the personality ID.
2. Set A to the remainder of Y divided by 4.
3. Divide Y by 256 and round down.
4. Set B to the remainder of Y divided by 4, then multiply B by 4.
5. Divide Y by 256 and round down.
6. Set C to the remainder of Y divided by 4, then multiply C by 16.
7. Divide Y by 256 and round down.
8. Set D to the remainder of Y divided by 4, then multiply D by 64.
9. Set X to A plus B plus C plus D.
10. Set X to the remainder of X divided by 28.

The result, X, contains the Unown form (where A through Z are 0-25, "!" is 26, and "?" is 27).

Wurmple

For a given Wurmple, if the remainder of the personality ID's high 16 bits divided by 10 is less than 5, it will evolve into Silcoon; else Cascoon.

Trainer ID

The trainer ID is 32 bits long. The player as well as each Pokémon can have a 32-bit trainer ID. A Pokémon's 32-bit trainer ID is set to the player's as the Pokémon is created, if it's owned by that player. A player's 32-bit trainer ID is set when a new game is started. However, the game only displays the lower 16 bits of a trainer ID (hereinafter called "public ID").

Many other Web sites use the term "ID number" or "trainer ID" to mean the portion of the number visible on the Trainer Card, even though the trainer ID, as used on this site, is 32 bits long. The "ID number" term used by those sites is 16 bits long and take the lower 16 bits of the 32-bit ID number. These sites also use another term, "secret ID", which is the portion of the ID that isn't visible and consists of the high 16 bits of the 32-bit ID number.

In generation 3, a Pokémon's 32-bit trainer ID and OT name (but not necessarily OT gender) must match those of the player in order to rename it with the Name Rater. In generation 4, however, the only condition for renaming a Pokémon using the Name Rater is that the Pokémon's public ID and the player's public ID must match. Neither the entire 32-bit trainer ID of the Pokémon and the player nor the OT names of the Pokémon and the player are required to match.

In generations 3 and 4, a Pokémon can disobey if, in addition to the player not having the appropriate badges, the Pokémon's 32-bit trainer ID and/or OT name (but not necessarily OT gender) are different from those of the player.

In generations 3 and 4, a Pokémon will gain extra Exp. Points (see below) if its 32-bit trainer ID and/or OT name (but not necessarily OT gender) are different from those of the player.

The Ruby, Sapphire, and Emerald versions say that a Pokémon was "obtained from a trade" if its 32-bit trainer ID, OT name, and/or OT gender are different from those of the player. The FireRed and LeafGreen versions say that a Pokémon was "obtained from a trade" merely if its 32-bit trainer ID and/or OT name are different from those of the player. Generation 4 games say that a Pokémon was "apparently" met, "apparently" hatched from an egg, or "apparently" had a fateful encounter (as the case may be) if its 32-bit trainer ID, OT name, and/or OT gender are different from those of the player. This doesn't apply if the Pokémon "arrived" from a different region.

Shiny Pokémon

There is a 1/8192 chance that the player will encounter a shiny Pokémon. Shiny Pokémon will have a different color from normal Pokémon.

To determine whether a Pokémon is shiny, the game splits the personality ID and 32-bit trainer ID each into two 16-bit halves, resulting in four numbers, A, B, C, and D. Then the game calculates "A xor B xor C xor D", resulting in another number, E. ("Xor" is the "exclusive OR" operation.) If E is less than 8, the Pokémon is shiny.

Stats

Types of Stats

There are six different types of stats:

HP (Hit Points)

A Pokémon with high HP is expected to last longer during battle. When a Pokémon's HP reaches 0, it faints and can't fight until it is revived.

Attack

The Attack stat affects the damage inflicted by physical attacks. If Attack is greater than the opponent's Defense, the physical attack's power is boosted. In generation 3, physical attacks have the types Normal, Fighting, Poison, Ground, Flying, Bug, Rock, Ghost, and Steel. In generation 4, an attack is generally physical if it either involves physical contact with the opponent (such as punches or kicks) or the attack's execution follows a law of physics (such as throwing objects, triggering a waterfall, and so on.)

Defense

The Defense stat affects the damage received from physical attacks. If Defense is greater than the attacker's Attack, the physical attack's power is reduced.

Special Attack

The Special Attack stat affects the damage inflicted by special attacks. If Special Attack is greater than the opponent's Special Defense, the special attack's power is boosted. In generation 3, special attacks have the types Fire, Water, Electric, Grass, Ice, Psychic, Dragon, and Dark. In generation 4, an attack is generally special if it either involves elemental magic such as earth, wind, water, fire, and electricity, or if the attack's execution doesn't necessarily follow a law of physics, such as psychic power, powerful beams, and so on.

Special Defense

The Special Defense stat affects the damage received from special attacks. If Special Defense is greater than the attacker's Special Attack, the special attack's power is reduced.

Speed

The Speed stat determines which Pokémon will strike first. In battle, most of the time, the Pokémon with the highest Speed attacks first in a particular round.

Stat Formulas

The game uses these formulas to find a Pokémon's stats. A Pokémon's stats are calculated whenever it gains a level or when the player encounters or receives it.

HP = floor((A*2+B+floor(C/4))*D/100)+D+10
Other Stats =floor((floor((A*2+B+floor(C/4))*D/100)+5)*E)

where:

• A = Pokémon's Base Stat
• B = Pokémon's Individual Value
• C = Pokémon's Effort Value
• D = Pokémon's Level
• E = 1.1 if the Pokémon's nature increases the stat; otherwise, 0.9 if the nature decreases the stat; otherwise, 1.
• floor(X) means "round X down to the nearest whole number."

As an exception, Shedinja's total HP is always 1 (its Base HP is 1).

Base Stats

Base stats are values that specify the stat potential of all Pokémon of the same Pokémon species and distinguish that species's stat potential from those of other species. There are six base stats for HP, Attack, Defense, Speed, Special Attack, and Special Defense. Each base stat ranges from 0 through 255.

View base stats for all Pokémon.

Individual Values

Individual Values, or IVs, range from 0 through 31. These values can differ between two Pokémon of the same species and define a particular Pokémon's stat potential rather than the stat potential of its species. There are six Individual Values for HP, Attack, Defense, Speed, Special Attack, and Special Defense. A Pokémon begins with randomly determined Individual Values.

For a level 100 Pokémon, each of its stats is increased by the Individual Value for that stat.

Effort Values

Effort Values, or EVs, indicate the amount of training that a Pokémon has made. Whenever a Pokémon earns Exp. Points in battle, usually by defeating foe Pokémon, it also earns a number of EVs depending on the species of the Pokémon defeated. The maximum EVs that a Pokémon can earn is 510. A Pokémon can earn up to 255 EVs per stat (HP, Attack, Defense, Speed, Special Attack, Special Defense). A Pokémon begins with Effort Values of 0 for all stats. For a level 100 Pokémon, every 4 EVs increase the corresponding stat by 1. Because of this, only 252 EVs in a certain stat (for a stat increase of 63) and 508 EVs overall are required to raise a Pokémon's stats as much as possible.

The stat enhancers (HP Up, Protein, Iron, Carbos, Calcium, and Zinc, respectively) increase the EVs of the respective stat by 10, but not to more than 100. Each stat enhancer only takes effect if the EV for that stat is less than 100. After a stat enhancer is used and takes effect, all the Pokémon's stats are recalculated. (Stat enhancers are also known as "vitamins".) Using HP Up won't have any effect on a Shedinja, however.

In the Emerald version and all generation 4 versions, certain Berries can decrease a Pokémon's effort values by 10 (Pomeg Berry, Kelpsy Berry, Qualot Berry, Tamato Berry, Hondew Berry, and Grepa Berry, respectively). After such a Berry is used and takes effect, all the Pokémon's stats are recalculated. In generation 4, these berries reduce the effort value to 100 (instead of by 10) if it's greater than 110. In generation 4, however, using a Pomeg Berry won't have any effect on a Shedinja, not even happiness gain, whereas in the Emerald version, Pomeg Berry will work as normal on Shedinja, even though the HP stat itself doesn't change.

The Macho Brace and the Pokérus virus each will double the EVs that a Pokémon will earn in battle. The Pokérus virus will double EVs this way even after the Pokémon is cured of the virus.

When a Pokémon has earned the maximum of 510 EVs, it can receive an Effort Ribbon in Slateport's outdoor market, in Sunyshore City, or in Blackthorn City.

In the generation 4 games, certain kinds of items will add 4 EVs of the appropriate stat to Pokémon that hold them whenever they earn EVs in battle, namely Power Weight, Power Bracer, Power Belt, Power Anklet, Power Lens, and Power Band, respectively. (These EVs are added before they're doubled by the Pokérus virus.)

When a Pokémon is placed in a PC storage box, the game saves, among other things, its Exp. Points (to calculate its level), its individual values, and the number of EVs it currently has for each stat. When the Pokémon is removed from the storage system, its stats are recalculated based on its EVs, without actually gaining a level. This effect is sometimes called the "box trick."

When Rare Candy is used on a Pokémon or when a Pokémon evolves or levels up, all of its stats are recalculated.

Effort Values are not obtained in battle when a Pokémon reaches level 100 (since it doesn't earn Exp. Points at that level). They are also not obtained while a Pokémon is deposited in the Day-Care or when a Rare Candy is used on it.

Experience

Whenever a Pokémon defeats another Pokémon, each Pokémon that participated in the battle against it gains Exp. Points (or experience points). The number of Exp. Points a Pokémon gains this way is based on a formula shown below.

Formula used if no Pokémon in party is holding an Exp. Share:

Exp. Points = int(int(L*G/7)/E)*X*Y*Z

Formula used if at least one unfainted Pokémon in party is holding an Exp. Share:

Exp. Points = (int(M/E)*A+int(M/F)*B)*X*Y*Z

where:

• L = Defeated Pokémon's level
• G = Defeated Pokémon's Base Experience
• X = If the battle is a Trainer battle, X=1.5; else 1.
• Y = If the participating Pokémon's 32-bit trainer ID and/or OT name are different from the player's 32-bit trainer ID, Y=1.5; else 1 ("[name] gained a boosted [value] Exp. Points!")
• Z = If the participating Pokémon is holding a Lucky Egg, Z=1.5; else 1.
• M = int(int(L*G/7)/2)
• E = Number of unfainted Pokémon that participated in the battle against the defeated Pokémon
• F = Number of unfainted Pokémon that are holding an Exp. Share
• A = If the Pokémon participated in the battle against the defeated Pokémon, A=1; else 0.
• B = If the participating Pokémon is holding an Exp. Share, B=1; else 0.

A "participant" means each unfainted Pokémon in the player's party who had seen the enemy Pokémon since the last time the enemy became active. A participant need not have used an attack against the Pokémon, but must merely have seen it. If a Pokémon faints at the same time as the enemy, it doesn't count as a participant. (In internal battles, if both teams have no Pokémon at the same time, it is considered a loss for the player.)

When a Pokémon gains a level, its current HP is its new HP minus the HP lost before the level gain.

While a Pokémon is in the Day-Care, it will earn 1 Exp. Point for each step the player walks and will learn new moves as it gains levels; such moves, if the list is full, will overwrite older moves, starting from the top of the list. (Even HM moves will be overwritten this way.)

Two growth rates were added in generation 3: their maximum experience values are 600,000 and 1,640,000.

In generation 4, if a Pokémon has a different 32-bit trainer ID and/or OT name from the player's and comes from a different language version from the player's, the Pokémon earns 1.7 times more Exp. Points than normal rather than 1.5 times more.

See the Experience table.

Size Calculation

The size of a Magikarp, Heracross, Barboach, and so on is calculated in two steps.

First, the game calculates the value of S with the formula below.

S = (((AT xor DF)*HP) xor M) * 256 + (((SA xor SD)*SP) xor N)

where:

• HP is the remainder of the HP individual value (IV) divided by 16.
• AT is the remainder of the Attack IV divided by 16.
• DF is the remainder of the Defense IV divided by 16.
• SP is the remainder of the Speed IV divided by 16.
• SA is the remainder of the Special Attack IV divided by 16.
• SD is the remainder of the Special Defense IV divided by 16.
• M is the remainder of the personality ID divided by 256 (the lowest byte of the ID).
• N is the remainder of (personality ID / 256) divided by 256 (the second lowest byte of the ID).
• "xor" represents an "exclusive OR" operation.

Then the game calculates the size of the Pokémon, in millimeters, using this formula:

Size = int(int((S-Z)/Y+X)*C/10)

where:

• C is the height of the Pokémon in tenths of a meter, as shown on the Pokédex.
• X, Y, and Z are based on the value of S as follows:
  • If S is from 0 through 9, then X=290, Y=1, Z=0.
  • If S is from 10 through 109, then X=300, Y=1, Z=10.
  • If S is from 110 through 309, then X=400, Y=2, Z=110.
  • If S is from 310 through 709, then X=500, Y=4, Z=310.
  • If S is from 710 through 2709, then X=600, Y=20, Z=710.
  • If S is from 2710 through 7709, then X=700, Y=50, Z=2710.
  • If S is from 7710 through 17709, then X=800, Y=100, Z=7710.
  • If S is from 17710 through 32709, then X=900, Y=150, Z=17710.
  • If S is from 32710 through 47709, then X=1000, Y=150, Z=32710.
  • If S is from 47710 through 57709, then X=1100, Y=100, Z=47710.
  • If S is from 57710 through 62709, then X=1200, Y=50, Z=57710.
  • If S is from 62710 through 64709, then X=1300, Y=20, Z=62710.
  • If S is from 64710 through 65209, then X=1400, Y=5, Z=64710.
  • If S is from 65210 through 65409, then X=1500, Y=2, Z=65210.
  • If S is from 65410 through 65535, then X=1700, Y=1, Z=65510.

Due to this formula, a Pokémon's actual size can range from 29% to 172.6% of its Pokédex height. The distribution is similar to a normal distribution, with a mean of about 100% and a standard deviation of about 17.9%. When converting to inches, the game rounds down to the nearest tenth of an inch.

Pokérus

Pokérus is a virus that infects Pokémon. There is a 3/65536 chance that a wild Pokémon will have Pokérus. If this happens, some of the Pokémon in the party may be infected with that virus after the battle ends. (Even eggs can be infected this way.) A Pokémon infected with or cured of Pokérus will earn twice as much EVs as normal in battle (see the "Effort Values" section).

Whenever a battle ends, for each Pokémon infected with Pokérus, there is a 1/3 chance that both the Pokémon before and after that Pokémon are also infected with Pokérus if not already infected. (Even eggs can be infected this way.) Walking with an infected Pokémon in the party or placing an infected Pokémon in a PC storage box won't infect other Pokémon.

At midnight in the DS games, or at midnight a few days later in the GBA games, the Pokémon is cured of Pokérus. Once a Pokémon is cured of Pokérus, it will never get it again (in the summary screen of such a Pokémon, a black dot in the GBA games, or a smiley face in the DS games, will appear). However, a Pokémon kept in a PC storage box will remain infected.

Notes on Evolution

A Pokémon gets only one opportunity to evolve when it levels up, even if it meets one or more conditions to evolve. For example, if a Zubat with a very high happiness reaches level 22, it evolves into Golbat, but not into Crobat afterward. It must wait until the next time it levels up to evolve into Crobat.

When Nincada evolves, if the player has a Poké Ball item and has a free space in the party, the Shedinja that appears is essentially a clone of the evolved Ninjask, except that it's a Shedinja named "SHEDINJA" rather than a Ninjask, has no ribbons, and appears in a Poké Ball. In particular, Shedinja has the same Individual Values, Effort Values, Exp. Points, personality ID, moves, and so on of the evolved Ninjask. (Shedinja is created after Ninjask learns any moves it would have upon evolution.)

An evolution caused by a trade or by using an item on a Pokémon can't be canceled.

In the FireRed and LeafGreen versions, if the player doesn't have the National Pokédex and Golbat and Chansey would try to evolve, instead it stops evolving.

Mirage Island

Once each day, the game generates a random number from 0 through 65535. Mirage Island will be "visible" (on Route 130, east of Pacifidlog Town) if that random number matches the lower 16 bits of the personality ID of at least one Pokémon in the player's party when Route 130 is entered.

Feebas

The player can fish for Feebas in only six randomly placed water tiles on Route 119. The exact location of these tiles changes whenever the "trendy phrase" changes. In each of these tiles, when fishing, Feebas will appear at a 50% chance; it doesn't matter which rod is used.

Encounters

This section applies to the Ruby and Sapphire versions.

Each area has a probability of Pokémon appearing, expressed as a value of 1, 4, 9, 10, 20, 25, 30, and 35. Whenever the player takes a step in which Pokémon could appear, the game uses this formula:

X = Y * 16

where:

• Y = Encounter value
• If a random number from 0 to 2874 exclusive is less than X, a Pokémon will appear.

Modifications

• If the Mach Bike or Acro Bike is used, multiply by 4/5.
• If the Black Flute had been used, multiply by 1/2. If the White Flute had been used, multiply by 3/2.
• If the first Pokémon in party has a Cleanse Tag, multiply by 2/3.
• If the first Pokémon in party has Stench, multiply by 1/2. If the first Pokémon in party has Illuminate, multiply by 2/3. (In either case, ignore if the Pokémon holds a Cleanse Tag.)

Places to Train

Here are suggested places to train Pokémon efficiently. Defeating the species given below at the given places will earn a Pokémon 1 or 2 Effort Values (EVs) for a specific stat.

Ruby/Sapphire/Emerald Version

• HP - Whismur (+1, Rusturf Tunnel); Marill (+1, Petalburg City water; Route 102/111/114/117/120 water)
• Attack - Trapinch (Route 111, desert); Poochyena (+1, Route 103); Shuppet (+1, Mt. Pyre, Sapphire/Emerald only)
• Defense - Clamperl (+1, underwater); Aron (+1, Granite Cave B1F/B2F)
• Speed - Zubat (+1, Meteor Falls entrance); Smeargle (+1, Artisan Cave, Emerald only); Magikarp (+1, Sootopolis City water)
• Special Attack - Numel (+1, Route 112); Spinda (+1, Route 113)
• Special Defense - Tentacool (+1, Routes 103/105/118/119/121/122/125/129/130 and so on, water)

FireRed/LeafGreen Version

• HP - Caterpie (+1, Viridian Forest), Wooper (+1, Ruin Valley/Four Island water)
• Attack - Paras (+1, Mt. Moon B1), Mankey (+1, Route 22/23)
• Defense - Tangela (+1, Route 21)
• Speed - Diglett (+1, Diglett's Cave), Zubat (+1, Mt. Moon)
• Special Attack - Gastly (+1, Pokemon Tower); Psyduck (+1, Celadon City water, Route 6/22/23/25 water, FireRed only)
• Special Defense - Special Defense - Tentacool (+1, Route 4/10/11/12/13/19/20/21/24 water); Hoppip (+1, Memorial Pillar)

Happiness

Happiness is a measure of a particular Pokémon's attachment to the player. When a Pokémon is created or traded from another player, it starts with its base happiness (normally 70 but depends on the species). A Pokémon hatched from an egg starts with a happiness of 120 instead. Happiness ranges from 0 through 255. Here are the ways to raise or lower happiness.

Method	Happiness 0-99	100-199	200-255
Level Up**	+5	+3	+2
Protein, Iron, Calcium, Carbos, Zinc, HP Up, PP Up, PP Max	+5	+3	+2
Pomeg/Kelpsy/Qualot/Tamato/Hondew/Grepa Berry (Emerald version)	+10	+5	+2
Daisy (in Pallet Town, after beating the game)	+3		+3
Begin a battle against a Gym Leader, Elite Four, or the Champion with the Pokémon in party (even if it doesn't participate or the battle ended in defeat)	+3		+1
Walk every 256 steps (50% chance)	+1
Heal Powder, Energy Powder	-5	-5	-10
Energy Root	-10	-10	-15
Revival Herb	-15	-15	-20
Pokémon faints	-1	-1	-1
Pokémon faints outside of battle due to poison	-5	-5	-5

If the Pokémon is holding a Soothe Bell, each happiness gain is multiplied by 1.5. Then, if the Pokémon was caught in a Luxury Ball, each happiness gain is increased by 1. Then, if the happiness gain occurs in the place where the Pokémon was caught, it's increased by 1.

A Pokémon that evolves through happiness will do so the next time it levels up and its happiness is 220 or more (after the battle ends, if any, and after adding happiness gain due to leveling up).

Breeding

These are notes related to discovering Pokémon eggs, also known as "breeding", in generation 3.

Egg Waiting Time

X depends on the species and 32-bit trainer ID of the Pokémon (the OT names and OT genders of each Pokémon are not considered):

• Same species, different ID: X=70% ("The two seem to get along very well.")
• Same species, same ID: X=50% ("The two seem to get along.")
• Different species, different ID: X=50% ("The two seem to get along.")
• Different species, same ID: X=20% ("The two don't seem to like each other.")

X will be 0% if the species are incompatible ("The two prefer to play with other Pokémon than each other"), that is, if one or both of the Pokémon are genderless, both have the same gender, or both species don't share the same "egg group". However, one of the Pokémon can be a Ditto (but not both) and the couple will remain compatible. X will also be 0% if either or both Pokémon belong in the "no eggs" egg group ("The two prefer to play with other Pokémon than each other"). A Ditto won't make the couple compatible in this case.

Every 256 steps after the two Pokémon are placed in the Day-Care, an egg will be ready at the percent chance given by X. The baby will be calculated as soon as the egg is received.

After an egg is received, an "egg counter" for that egg is set to the "steps to hatch egg" divided by 256. Every 256 steps after an egg is taken or rejected from the Day-Care Man, the game reduces the "egg counter" of each egg in the player's party by 1. If an egg's "egg counter" reaches 0 or less, it hatches, and the "egg counters" of eggs that follow it in order in the player's party are not reduced. When an egg hatches, its 32-bit trainer ID, OT name, and OT gender change to those of the player, and the player will be allowed to nickname the newly hatched Pokémon.

The Summary screen gives an estimate of how long before a given egg hatches:

• Egg counter is 41 or greater: "It looks like this EGG will take a long time to hatch."
• Egg counter is 11-40: "What will hatch from this? It will take some time."
• Egg counter is 6-10: "It moves occasionally. It should hatch soon."
• Egg counter is 5 or less: "It's making sounds. It's about to hatch!"

Species

The species hatched from the egg is usually that of the female, in the lowest evolutionary stage. There are a few exceptions:

1. One of the Pokémon can be a Ditto, but not both. In that case, the baby will be the species that isn't the Ditto, in the lowest evolutionary stage.
2. If the baby species would be Nidoran female, instead it's either Nidoran male or Nidoran female.
3. If the baby species would be Illumise, instead it's either Illumise or Volbeat.
4. If neither parent is holding a Lax Incense and the baby species would be Wynaut, the baby species is Wobbuffet instead.
5. If neither parent is holding a Sea Incense and the baby species would be Azurill, the baby species is Marill instead.

Moves

The baby begins at level 5 and initially has all moves it would have at level 5. The baby can inherit other moves from its parents, in this order:

1. The baby will inherit a move if the father* knows it and it's an egg move for the baby's species.
2. The baby will inherit a move if the father* knows it and it can be taught to the baby's species through a TM or HM.
3. The baby will inherit a move if both parents know it and the baby's species could learn it by leveling up.
4. In the Emerald version, if either parent is a Pikachu or Raichu and holds a Light Ball and the baby is a Pichu, the baby will learn Volt Tackle.

If the baby would have more than four moves this way, moves from the top of the list are deleted and all duplicates except the last are removed until four moves remain.

*In these two cases, if one of the parents is a Ditto, moves can be inherited even if the other parent is genderless, but not if the other parent is female.

Individual Values

The baby inherits three Individual Values. In the Emerald version, it receives random IVs, then it inherits a random IV from either parent, then a random IV other than HP from either parent, then a random IV other than HP or Defense from either parent. In the Ruby, Sapphire, FireRed, and LeafGreen versions, it receives random IVs, then it inherits three IVs for three different stats, each from either parent.

Personality ID

Except in the Emerald version, the two low-order bytes of the baby's personality ID are never both equal to 0.

Nature

A random nature is chosen for the baby, indirectly through generation of a personality ID.

As an exception, in the Emerald version, there is a (32767/65536) chance that the baby will gain the nature of the holder of Everstone if that holder is a Ditto, if one exists, or the baby's mother if neither parent is a Ditto. (The chance is instead 32769/65536 if the Ditto is the first Pokémon deposited to the Day Care.) This case is handled by recalculating the baby's personality ID up to 2400 times until the nature is the same and the personality ID's high-order 2 bytes do not equal 0.

Deoxys

Deoxys can assume different forms depending on the version of Pokemon where it exists. Each form has different base stats and moves learned.

Name	HP	Atk	Def	Sp.Atk	Sp.Def	Speed	Version
Deoxys Normal Form	50	150	50	150	50	150	Ruby/Sapphire
Deoxys Attack Form	50	180	20	180	20	150	FireRed
Deoxys Defense Form	50	70	160	70	160	90	LeafGreen
Deoxys Speed Form	50	95	90	95	90	180	Emerald

Moves Learned

• Normal Form: Leer (1), Wrap (1), Night Shade (5), Teleport (10), Knock Off (15), Pursuit (20), Psychic (25), Snatch (30), Cosmic Power (35), Recover (40), Psycho Boost (45), Hyper Beam (50)
• Attack Form: Leer (1), Wrap (1), Night Shade (5), Teleport (10), Taunt (15), Pursuit (20), Psychic (25), Superpower (30), Cosmic Power (35), Zap Cannon (40), Psycho Boost (45), Hyper Beam (50)
• Defense Form: Leer (1), Wrap (1), Night Shade (5), Teleport (10), Knock Off (15), Spikes (20), Psychic (25), Snatch (30), Iron Defense (35), Amnesia (35), Recover (40), Psycho Boost (45), Counter (50), Mirror Coat (50)
• Speed Form: Leer (1), Wrap (1), Night Shade (5), Double Team (10), Knock Off (15), Pursuit (20), Psychic (25), Swift (30), Agility (35), Recover (40), Psycho Boost (45), ExtremeSpeed (50)

Shadow Pokémon

Pokémon Colosseum and XD include a mechanic that uses Shadow Pokémon and Shadow moves. In Colosseum, the Shadow type has no weaknesses, resistances, or immunities. In XD, every type except Shadow has the Shadow type as a weakness and the Shadow type is resistant to itself.

In Pokémon Colosseum, there's only one Shadow move, Shadow Rush. Pokémon XD includes several other Shadow moves.

Each Shadow move's PP is virtually unlimited. All moves shown below have the type Shadow, but some moves can be physical and others special.

Name	Cat	Pwr	Acc	Eff	Tgt	Flags
Deals damage.
SHADOW BLITZ	Physical	40	100	0	Single non-user	bef
SHADOW STORM	Special	95	100	0	All opponents	b
SHADOW WAVE	Special	50	100	0	All opponents	b
SHADOW RAVE	Special	70	100	0	All opponents	be
SHADOW BREAK	Physical	75	100	0	Single non-user	bef
Good chance for a critical hit.
SHADOW BLAST	Special	80	100	0	Single non-user	bef
Colosseum: If this attack is successful, user loses 1/4 of HP lost by opponent due to this attack, but not less than 1 HP (recoil). If user is in Hyper Mode, this attack has a good chance for a critical hit.
SHADOW RUSH	Physical	100	90	0	Single non-user	abef
XD: Deals damage.
SHADOW RUSH	Physical	55	100	0	All opponents	abef
Decreases opponent's evasiveness by 2 stages.
SHADOW MIST	Non-damaging	0	100	0	All opponents	be
Decreases opponent's Defense by 2 stages.
SHADOW DOWN	Non-damaging	0	100	0	All opponents	be
Ends the effects of Reflect, Light Screen, and Safeguard on the opposing Pokémon's side.
SHADOW SHED	Non-damaging	0	100	0	Opposing side
During effect, opponent cannot switch or flee. Effect ends when user or opponent is switched. During effect, this attack fails against opponent.
SHADOW HOLD	Non-damaging	0	80	0	All opponents	be
May burn opponent.
SHADOW FIRE	Special	75	100	10	Single non-user	bef
May freeze opponent.
SHADOW CHILL	Special	75	100	10	Single non-user	bef
May paralyze opponent.
SHADOW BOLT	Special	75	100	10	Single non-user	bef
Confuses opponent.
SHADOW PANIC	Non-damaging	0	90	0	All opponents	be
If this attack is successful, user loses half of its current HP [recoil damage? Test Marowak with Shadow End].
SHADOW END	Physical	120	60	0	Single non-user	abef
Each active Pokémon loses half of its current HP, rounded down. If this attack is successful, on the next round, user can't take any action and does nothing during its turn. (That move is prevented from being used during that turn.)
SHADOW HALF	Non-damaging	0	100	0	User
Weather. Lasts for [five] rounds, including the current round. During effect, each active non-shadow Pokémon loses [1/16] of total HP at the end of every round.
SHADOW SKY	Non-damaging	0	100	0	User