Pokemon Ruby/Sapphire - Various Notes

The ID modulo 25 identifies the nature of a Pokemon. Shown here are the taste preferences of Pokemon with those natures (what PokeBlocks they like), and the stats to increase and decrease.

Hex	Nature	Like	Dislike	Stat increase	Stat decrease
00	Hardy	(neutral)
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	(neutral)
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	(neutral)
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	(neutral)
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	(neutral)

Note that preference to certain tastes affects a Pokemon's stats. For instance, if a Pokemon's nature indicates that it likes spicy, its Attack will increase, but if not, its Attack will decrease.

The low byte of the ID contains the Pokemon's gender value. According to the Pokemon, this byte could mean that the Pokemon is male or female.

If Pokemon species is...	Range of female
12.5% female	0-30
25% female	0-63
50% female	0-126
75% female	0-190

Of course, this byte is ignored if the species is genderless, always male, or always female. A Pokemon can have no gender at all, if it was obtained from Mirage Island. In that case, the gender value will be 0.

To find the Unown shape, take the lowest two bits in each byte of the ID, and combine them together:

A=(id>>24)&0x03;
B=(id>>16)&0x03;
C=(id>>8 )&0x03;
D=(id    )&0x03;
Unown=D|(C<<2)|(B<<4)|(A<<6);

The lowest 5 bits of the resulting byte contains the Unown shape.

Individual Values range from 0 to 31. These values are important in determining the Pokemon's final stats. There are six Individual Values for HP, Attack, Defense, Speed, Special Attack, and Special Defense. They are randomly determined when you encounter a wild Pokemon or obtain a Pokemon internally.

Finding Individual Values

The Effort Values or EVs, indicate the amount of training that a Pokemon has made. Whenever a foe Pokemon is defeated in an internal battle (wild or trainer), each Pokemon that participated in the battle against it will earn a number of EVs depending on the species of the Pokemon defeated. The limit that a Pokemon can earn is 510. A Pokemon can earn up to 255 EVs per stat (HP, Attack, Defense, Speed, Special Attack, Special Defense). A Pokemon begins with Effort Values of 0 for all stats. According to the stat formula (above), for a level 100 Pokemon, every 4 EVs increase the corresponding stat by 1.

The stat enhancers (HP Up, Protein, Iron, Carbos, Calcium, and Zinc, respectively) increase the EVs of the respective stat by 10. 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, the Pokemon's stats are recalculated. (Stat enhancers are also known as "vitamins".)

In the Emerald version, certain Berries can decrease a Pokemon's effort values by 10 (Pomeg Berry, Kelpsy Berry, Qualot Berry, Tamato Berry, Hondew Berry, and Grepa Berry, respectively).

The Macho Brace and the PokeRus virus each will double the EVs that a Pokemon will earn.

If a Pokemon is holding an Exp. Share, it will earn EVs as though it were one of the battle's participants. (If it has the PokeRus virus, its EV gain is doubled as usual.)

When your Pokemon has earned the maximum of 510 EVs, it can receive an Effort Ribbon in Slateport's outdoor market.

Rare Candy, like other methods of level gain, uses the Effort Values in stat calculation, contrary to rumors.

Effort Values are not obtained in battle when a Pokemon reaches level 100.

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

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

where:

• A = Pokemon's Base Stat
• B = Pokemon's Individual Value
• C = Pokemon's Effort Value
• D = Pokemon's Level
• E = Normally equal to 1.

If the Pokemon's nature increases the stat by 10%, E = (110/100).
If the Pokemon's nature decreases the stat by 10%, E = (90/100).

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

The trainer ID is 32 bits long. Only the lower 16 bits is visible - on the player's Trainer Card.

There is a 1/8192 chance that you will encounter a shiny Pokemon. Unlike in Gold/Silver/Crystal versions, whether a Pokemon is shiny is not based on its Individual Values. Shiny Pokemon will have a different color from normal Pokemon.

Shininess is based on the personality ID and the 32-bit trainer ID:

 A = PersonalityID XOR TrainerID
 B = A AND 0xFFFF
 C = (A >> 16) AND 0xFFFF
 D = B XOR C
 SHINY = (D < 8)

Breeding in Ruby and Sapphire is similar to breeding in previous versions.

Egg Waiting Time

X depends on the species and trainer ID of the Pokemon:

• Same species, different ID: X=70
• Same species, same ID: X=50
• Different species, different ID: X=50
• Different species, same ID: X=20

Every 256 steps after the two Pokemon are placed in the daycare, an egg will be ready if a random number from 0 through 99 is less than X. The baby will be calculated as soon as the egg is received.

Species

Ability

Moves

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

• The baby will inherit a move if the father knows it and it's an egg move for the baby's species.
• 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.
• The baby will inherit a move if both the mother and father know it and the baby's species could learn it by leveling up.
• In the Emerald version, if the father is a Pikachu and holds a Light Ball and the baby is a Pichu, the baby will learn Volt Tackle.

Individual Values

The baby inherits three Individual Values corresponding to a different stat from among HP, Attack, Defense, Speed, Special Attack, and Special Defense. Each of these Individual Values is inherited from either the mother or father.

Except in the Emerald version, however, the same stat can be chosen again because the last stat chosen before is overwritten in the process of choosing three random stats.

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 or the baby's mother. 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.