What release date had originally been planned for Pocket Monsters Red and Green before the delay?

Pocket Monsters Red and Green had originally been planned for release on December 21, 1995, before being delayed to February 27, 1996.

The delay occurred because derivative products were not yet ready for sale. Rather than launch the games without the surrounding merchandise and promotional products, Nintendo and its partners postponed the release. The games eventually appeared in Japan for the Game Boy in February 1996.

That final February date became the recognized beginning of the Pokémon video game series and the basis for anniversary celebrations. The delay itself is an important part of the franchise's history because Pokémon was designed from the start to connect games with trading, cards, characters, and merchandise.

After the Japanese launch, Pokémon Blue was released in Japan as a special edition and later used as the basis for the international Red and Blue versions. The original Japanese Green version was not released internationally.