Base Set (Japanese: 拡張パックExpansion Pack) is the name given to the original core release of cards and Theme Decks for the Pokémon Trading Card Game. It was released in Japan on October 20, 1996, and in the United States on January 9, 1999.
An advertisement for the original Japanese release
While this expansion officially introduced the TCG to the United States in January 1999, many stores were initially reluctant to sell the game. As a result, it did not see a widespread release until March or April of that year.
The 1st Edition print run sold extremely quickly, making first edition Base Set cards some of the most sought-after of all of the early TCG expansions.
The Shadowless print mirror the 1st Edition cards except for the 1st Edition logo. All cards in the 1st Edition and Shadowless runs were printed with thinner HP and attack text. These cards were without drop shadows for the illustration window, hence the name shadowless. Shadowless cards are more valuable than later runs.
The Unlimited print is the most common print of the Base Set.
There was a 4th print run that mirror the Unlimited print except the date in the bottom right corner says 1999-2000. This print was released in other countries such as the United Kingdom and Australia.
This expansion was replaced by Base Set 2 on its release, as by that point Base Set had been out of print for some time.
Several final form Pokémon were left out of this set despite their pre-evolved forms appearing - Butterfree, Clefable, Dodrio, Dragonite, Gengar, Hypno, Pidgeot, Rapidash, Sandslash and Weezing. These cards were later released in Jungle and Fossil.
Changes between the Japanese and international release
In TCG expansions up until Pokémon VS, the Japanese cards did not have a numbering system, and so the only number featured on the Japanese cards is the Pokémon's Pokédex number.
The English cards adopted a system based on ordering the cards alphabetically and by descending rarity (rare-holo, rare, uncommon, common) and class of card (Pokémon, Trainer, Energy). This ordering remained in place until the release of Black & White. The Japanese set is ordered by type (Grass, Fire, Water, Lightning, Psychic, Fighting, Colorless), National Pokédex number, and ascending rarity (rare and rare-holo counting the same). This ordering remained in place until e-Card 2.