Start/End Dates	2012-12-20 through 2013-02-21
Country	United States

Details

The official Pokémon website announced that people that participated in the Pokémon League events could get access to a special Scizor that knows Steel Wing and Pursuit.

Cool Pokémon for Pokémon League Players!

There are now even more reasons to start playing in your local Pokémon League—cool Pokémon!

Participate in Pokémon League events to get special access to awesome Pokémon in the Pokémon Global Link! Right now, if you play at a Pokémon League event during the ongoing Aspertia Gym Season, you'll qualify to get a tough Scizor with a great set of moves, including Steel Wing and Pursuit. Then, between December 20, 2012, and February 21, 2013, visit the Pokémon Global Link to get Scizor. Be sure to visit during later seasons for more tough Pokémon!

All you need is a Pokémon Trainer Club account and a copy of Pokémon Black Version 2, Pokémon White Version 2, Pokémon Black Version, or Pokémon White Version registered at the Pokémon Global Link.

Source: http://www.pokemon.com/us/pokemon-news/op_2012_league_pokemon_distribution-2012-11-13/

League Players: Get Your Scizor!

A tough and battle-ready Scizor is waiting for Pokémon League players! If you are registered as having played at a Pokémon League event, you automatically qualify for this Scizor. All you have to do to get this Pokémon is go to the Promotions page at the Pokémon Global Link and follow the instructions. The next time you use Game Sync, Scizor will be added to your game!

Source: http://en.pokemon-gl.com/#/information/540