Which magazine announced the first public Mew promotion for Pokémon Red and Green?

CoroCoro Comic announced the first public Mew promotion for Pokémon Red and Green.

Mew was a secret Pokémon added late in development. It was hidden in the original games and was not intended to be obtained through normal gameplay. After the games launched, the May 1996 issue of CoroCoro Comic publicized a promotion centered on the mysterious Pokémon.

Readers could enter the promotion by sending a postcard, and 20 winners were selected. The winning cartridges were returned so Mew could be uploaded onto them. This unusual process helped turn Mew into a rumor-generating secret and increased interest in the games.

The promotion is often confused with later official distributions. Nintendo and other partners eventually distributed Mew through additional events, but CoroCoro Comic was the publication tied to the first major public announcement.