The Yu-Gi-Oh! OCG and Rush Duel are doing a collaboration campaign with Seven Eleven. By buying any combination of the featured Hi-Chew products, you can obtain 1 of the following promos:

OCG cards:
Dark Magician
Buster Blader
Dark Paladin
Marshmallon

Rush Duel cards:
Gaia the Fierce Knight
Curse of Dragon
Gaia the Dragon Champion

These will have very limited availability, with only 4 copies of each card available in each store, first come, first served. The campaign will run for August 3rd to August 16th.

Source.