e-Reader cards, explained
Dot codes
Between 2001 and 2004, Pokémon cards shipped with data printed on them. The dotted strips along the border are machine-readable code — swipe the card through Nintendo's e-Reader, a Game Boy Advance peripheral, and it loads what's on the strip.
What the strips hold
Mini-games, Pokédex entries, attack animations, extras that never existed anywhere else. Some content spans several cards — you scan a sequence to unlock it. The cards play fine in the TCG without ever being scanned; the strip is a bonus layer, not a requirement.
Which sets carry them
The Japanese e-series expansions and their English counterparts — Expedition, Aquapolis, Skyridge — are the core run. The English three are the last sets Wizards of the Coast printed, which is part of why they're chased: end of an era, and a data gimmick nobody repeated.
Why edges matter here
The code lives on the border, so this is the one era where edgewear sits directly on the printed data. Condition reads the same as any other card — the condition guide applies — but an e-Reader card's edges deserve a second look before you buy or sell.