Pokémon Ruby Version, Sapphire Version, and Emerald Version - Breeding

Tags: pokemon-ruby-sapphire-and-emerald, in-depth-guides, breeding

These are notes related to discovering Pokémon Eggs, also known as "breeding", in Pokémon Ruby Version, Pokémon Sapphire Version, and Pokémon Emerald Version.

Egg Waiting Time

The waiting time depends on the species and 32-bit Trainer ID of the Pokémon (the OT names and OT genders of each Pokémon are not considered). The species and ID will set a value, called X, as follows:

• 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.")

However, if the Pokémon are incompatible, X will be 0% instead ("The two prefer to play with other Pokémon than each other"). This will happen if:

• Both Pokémon are male or both are female.
• Both Pokémon are Ditto.
• One or both of the Pokémon are gender-unknown, unless either Pokémon is a Ditto.
• The two Pokémon don’t have an Egg group in common, unless either Pokémon is a Ditto.
• One or both of the Pokémon are in the "undiscovered" Egg group, even if either Pokémon is a Ditto.

If the two Pokémon are compatible, then 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 Egg 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, or if it’s Pokémon Emerald Version and a Pokémon with Magma Armor or Flame Body is in the player’s party, by 2. 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

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

Moves

The Egg begins at level 5 and initially has all moves it would have up to level 5. The Egg can inherit other moves from the Pokémon left in the Day-Care, in this order:

1. The Egg will inherit all moves that the male Pokémon* knows and that are Egg moves for the Egg’s species.
2. The Egg will inherit all moves that the male Pokémon* knows and that can be taught to the Egg’s species through a TM or HM.
3. The Egg will inherit all moves that both Pokémon left in the Day-Care know and that the Egg’s species could learn by leveling up.
4. In Pokémon Emerald Version, if either Pokémon in the pair is a Pikachu or Raichu and holds a Light Ball and the Egg is a Pichu, the Egg will learn Volt Tackle.

If the Egg 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 Pokémon in the pair is a Ditto, moves will be inherited by the Pokémon that isn’t Ditto, but only if it’s male or gender-unknown.

Individual Values

The Egg inherits three Individual Values. In Pokémon Emerald Version, it receives random IVs, then it inherits a random IV from either Pokémon in the pair, then a random IV other than HP from either Pokémon in the pair, then a random IV other than HP or Defense from either Pokémon in the pair. In Pokémon Ruby Version, Pokémon Sapphire Version, Pokémon FireRed Version, and Pokémon LeafGreen Version, it receives random IVs, then it inherits three IVs for three different stats, each from either Pokémon in the pair.

Personality ID

Except in Pokémon Emerald Version, the remainder of the Egg’s personality ID divided by 65536 is never equal to 0.

Nature

A random nature is chosen for the Egg, indirectly by generating a personality ID.

As an exception, in Pokémon Emerald Version, there is a (32767/65536) chance that the Egg will gain the nature of the holder of Everstone if that holder is a Ditto, if one exists, or the female Pokémon if neither Pokémon in the pair 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 Egg’s personality ID up to 2400 times until the nature is the same and the personality ID divided by 65536, rounded down, doesn’t equal 0.