Pokémon Black Version and Pokémon White Version - Shiny Pokémon
There is a 1/8192 chance that a Pokémon generated by the game will be Shiny. 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 an "exclusive or" operation; see "Size Calculation" below.) If E is less than 8, the Pokémon is Shiny.