Pokémon Gold, Silver, and Crystal - Notes

Evolution

Some Pokémon can evolve:

1. At the end of any battle (except battles the player lost) in which the Pokémon levels up or after a Rare Candy is used on it and takes effect;
2. When a certain item is used on it; or
3. When the Pokémon is traded to another game.

Those are the three basic ways that Pokémon can evolve. Here is a more detailed list.

• Case 1 (The Pokémon levels up). The evolution can be canceled by pressing B while the Pokémon evolves.
  • The Pokémon is at or above a certain level (most Pokémon)
    • And Attack is greater than Defense (Hitmonlee), or Attack is less than Defense (Hitmonchan), or Attack is equal to Defense (Hitmontop).
  • The Pokémon's friendship is 220 or more (example: Chansey)
    • And it's day (Espeon), or night (Umbreon). Here, day is from 4:00 a.m. through 5:59 p.m., and night is from 6:00 p.m. through 3:59 a.m.
• Case 2 (The Pokémon is traded). The evolution can't be canceled.
  • The Pokémon is traded to another game (example: Machoke).
  • The Pokémon is traded to another game while holding a certain item (example: Scizor). If the Pokémon evolves this way, that item is removed from it.
• Case 3 (A certain item is used on the Pokémon). An example is Pikachu. The evolution can't be canceled.

Special notes:

• Day-Care: A Pokémon placed in the Day-Care won't evolve, even if it gains enough Exp. Points for its level to go up.
• Everstone: A Pokémon holding Everstone won't evolve, even if it evolves using an item and the player uses that item on it.
• Double 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 friendship 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.
• Name Change: If a Pokémon whose nickname is the same as its old species's name in a game in a certain language evolves in that game, or is traded to another game and evolves in that game, then the Pokémon's name changes to the name of the new species in the language of the game where the Pokémon evolves. (Pokémon names are in upper-case letters in the generation 1 and 2 games, so upper-case letters are distinct from lower-case letters.) No other case can make a Pokémon's name change upon evolution.

Times of Day

Morning is from 4:00 a.m. through 9:59 a.m. Day is from 10:00 a.m. through 5:59 p.m. Night is from 6:00 p.m. through 3:59 a.m.

Pokérus

Pokérus is a virus that infects Pokémon. There is a 3/65536 chance that a Pokémon will become infected with Pokérus at the end of a battle in which Exp. Points can be gained.. (Even eggs can be infected this way.) A Pokémon infected with or cured of Pokérus will earn twice as much stat experience as normal in battle.

Infected Pokémon have a status that reads Pokérus. (However, Pokérus is not a status problem.) When the player tries to heal the infected Pokémon in a Pokémon Center, the receptionist will say:

Your Pokémon appear to have tiny life forms stuck to them. Your Pokémon are healthy and seem to be fine. But we can't tell you anything more at a Pokémon Center.

I discovered an odd thing. Apparently there's something called Pokérus that infects Pokémon. Yes, it's like a virus, so it's called Pokérus. It multiplies fast and infects other Pokémon too. But that's all. It doesn't seem to do anything, and it goes away over time. I guess it's nothing to worry about. Bye!

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. The game checks whether this condition will apply for each Pokémon already infected before infecting others if necessary.) Walking with an infected Pokémon in the party or placing an infected Pokémon in a PC storage box won't infect other Pokémon.

Within four days, at midnight, the Pokémon is cured of Pokérus. Once a Pokémon is cured of Pokérus, it will never get it again (in the stats screen of such a Pokémon, a black dot will appear). However, a Pokémon kept in a PC storage box will remain infected.

Pokégear Phone

When will Mom call the hero?

How often will trainers call?

Trainers appear to call you every half hour. They appear to call whenever you step out of a building, fly, finish a battle, or ride the train. The calls might not be triggered by steps. Decision of which trainer will call is random.

Headbutt

Odds of Getting a Pokémon

X = Tree's X coordinate
Y = Tree's Y coordinate
A = ((X*Y+X+Y)/5)%10
B = (Player's ID Number)%10

When A = B chances of Pokémon coming out is 8/10
When A > B and A - B < 5, probability is 5/10
When A < B and A - B > 5, probability is 5/10
For any other case, probability is 1/10
(in other words, 1 out of 10 trees will produce many Pokémon.)

Pokémon Species

There are two types of Pokémon you'll find when you headbutt trees.

• Forest: Azalea Town, Lake of Rage, Ilex Forest, Routes 26, 27, 34, 35, 36, 37, 38, 39
• Mountain: Routes 29, 30, 31, 32, 33, 42, 43, 44, 45, 46

The Pokémon you find when you headbutt trees will always be Level 10.

Legendary Trio of Johto

Whenever the map changes; whenever the game is restarted; or, at a 1/16 chance, whenever a battle ends, each Pokémon of the Legendary Trio (Raikou, Entei, Suicune) moves to the next route on the map where the player wasn't found two times ago. At a 1/32 chance, that Pokémon may instead move to a random route on the map where the player wasn't found two times ago. The list below shows the possible destinations (the numbers below are route numbers).

• 29 → 30, 46
• 30 → 29, 31
• 31 → 30, 32, 36
• 32 → 31, 33, 36
• 33 → 32, 34
• 34 → 33, 35
• 35 → 34, 36
• 36 → 31, 32, 35, 37
• 37 → 36, 38, 42
• 38 → 37, 39, 42
• 39 → 38
• 42 → 37, 38, 43, 44
• 43 → 42, 44
• 44 → 42, 43, 45
• 45 → 44, 46
• 46 → 29, 45

Magikarp's Length

The size of a Magikarp in Generation II is calculated in two steps. First, the game calculates two numbers called B and C as follows.

B=RRC(RRC(AT * 16 + DF)) xor RRC(V)
C=RRC(RRC(SP * 16 + SC)) xor RRC(W)

• V is the Pokémon's ID divided by 256 and rounded down (the high byte of the ID).
• W is the remainder of the Pokémon's ID divided by 256 (the low byte of the ID).
• AT is the Attack diversification value (DV, individual value).
• DF is the Defense DV.
• SP is the Speed DV.
• SC is the Special DV.
• "xor" is an "exclusive OR" operation:
  1. Let A and B be the two numbers on either side of the "xor", let C be 1, and let R be 0.
  2. If A is odd and B is even, or vice versa, add C to R.
  3. Multiply C by 2, and divide A and B each by 2, rounding down.
  4. Repeat steps 2 and 3 until A and B are both 0.
  5. The result of the "exclusive or" operation is R.
• "RRC" is a right rotate carry operation performed on bytes. It is equivalent to dividing the value by 2, rounding down, and adding 128 to the result if the original value is odd.

Then the game figures out the size based on the values of B and C. There are two special cases here. If B is 0 and C is less than 10, then the size is equal to C plus 190 millimeters. Otherwise, if B is 255, then the size is equal to C plus 1370 millimeters. Otherwise, the size in millimeters is determined using the following formula:

Size = Z * 100 + int(((65536+(B * 256 + C)-X)%65536)/Y) % 256

where "%" is the remainder operator, and where X, Y, and Z depend on the value of B as follows:

• If B is 0, then X = 310, Y = 2, Z = 3.
• If B is 1, then X = 710, Y = 4, Z = 4.
• If B is 2 through 9, then X = 2710, Y = 20, Z = 5.
• If B is 10 through 29, then X = 7710, Y = 50, Z = 6.
• If B is 30 through 68, then X = 17710, Y = 100, Z = 7.
• If B is 69 through 126, then X = 32710, Y = 150, Z = 8.
• If B is 127 through 185, then X = 47710, Y = 150, Z = 9.
• If B is 186 through 224, then X = 57710, Y = 100, Z = 10.
• If B is 225 through 243, then X = 62710, Y = 50, Z = 11.
• If B is 244 through 251, then X = 64710, Y = 20, Z = 12.
• If B is 252 through 253, then X = 65210, Y = 5, Z = 13.
• If B is 254, then X = 65410, Y = 2, Z = 14.

When the value is converted to inches (1 inch = 25.4 mm), it's rounded down to the nearest inch.

Radio

Pokémon March doubles the encounter rate of wild battles, and Pokémon Lullaby halves the encounter rate of wild battles.

Lucky Number Show

You can earn different prizes in the Lucky Number Show if one of your Pokémon's ID numbers match the winning number. Here is the complete list:
If last 2 digits (in decimal) match, you'll win a PP Up.
If last 3 digits match, you'll win an Exp.Share.
The game doesn't check if last four digits match.
If last 5 digits match, you'll win a Master Ball.

The Pokémon with the winning ID need not be in your party, but can also be in the currently selected PC box.

Gender Ratios

If a Pokémon's Attack diversification value (individual value) is within the "Female Range" for its species, the Pokémon will be female.

Unown

This is the formula to find the form of an Unown:

UnownLetter = ((A+B+C+D)/10)+1

where A, B, C, and D are based on the Pokémon's diversification values (individual values) as follows:

The result, UnownLetter, is the position in the alphabet of the Unown shape (for example "A" if the result is 1).

Bug Catching Contest

This formula calculates the amount of points a bug Pokémon will earn in the Bug Catching Contest.

(Maximum HP * 4) + Attack + Defense + Speed + Sp.Attack + Sp.Defense + A + int(Current HP/8)+B

A is based on the diversification values (DVs, individual values) of the caught Pokémon:

• A starts with 0.
• If half the Defense DV, rounded down, is odd, add 16 to A.
• If half the Attack DV, rounded down, is odd, add 8 to A.
• If half the Special DV, rounded down, is odd, add 4 to A.
• If half the Speed DV, rounded down, is odd, add 1 to A.

If the Pokémon is holding an item, B is 1; otherwise B is 0.

The game truncates each stat (including total and current HP) to the lowest 8 bits for the purposes of this formula.

Trainer ID and OT Name

The trainer ID is 16 bits long. The player as well as each Pokémon can have a trainer ID. A Pokémon's trainer ID is set to the player's as the Pokémon is created, if it's owned by that player. A player's trainer ID is set when a new game is started.

Each Pokémon also comes with an Original Trainer name ("OT name"). This value, like the Trainer ID, is set to that of the player as a Pokémon owned by that player is created.

A Pokémon's trainer ID and OT name must match those of the player in order to rename it with the Name Rater.

A Pokémon can disobey if, in addition to the player not having the appropriate badges, the Pokémon's trainer ID is different from that of the player (see "Obedience check").

A Pokémon will gain extra Exp. Points (see the page "Exp. Points") if its trainer ID is different from that of the player.

Friendship

There is a special value called "friendship" that determines how friendly a certain Pokémon is toward the player. However, it's not easy to find out a Pokémon's exact friendship without a little work.

To get an idea of friendship, talk to the lady in east-central Goldenrod City and she'll check the first Pokémon in the party. What she says will determine the approximate friendship of that Pokémon.

Pokémon caught with the Friend Ball start with a friendship of 200; other Pokémon start with their base friendship (in Gold/Silver/Crystal, the base friendship is always 70). A Pokémon hatched from an egg starts with a friendship of 120. Friendship ranges from 0 through 255. Here are the ways to raise or lower friendship.

*60%, 30%, and 10% chance, respectively.

**In the Crystal version, friendship gain is doubled if the Pokémon levels up at the place at which it first appeared in the game. To find out where, visit the Pokémon Seer in Cianwood City.

Repel

Max Repel, Repel, and Super Repel prevent wild encounters with Pokémon whose level is at or less than the level of the first Pokémon in the player's party that isn't an egg and hasn't fainted for 250, 100, and 200 steps, respectively, after use.

Fishing

Anywhere a wild Pokémon could appear while fishing, each fishing attempt is successful at a 50% chance.