Long before anyone was checking for a First Edition stamp, some of the very earliest Base Set cards were printed with a design detail simply missing.
A shadow that wasn't there yet
Standard Base Set cards carry a subtle drop shadow along the right and bottom edge of the artwork's inner border. On the earliest copies printed, that shadow is reportedly absent entirely — not a fault, just an artwork detail added partway through the set's original production run.
A separate detail from the First Edition stamp
Shadowless status and the First Edition stamp both mark early copies, but they aren't the same thing. Because the shadow was reportedly added mid-run, some early Unlimited-print cards are shadowless too, without carrying a First Edition stamp at all — making shadowless its own distinct, and separately collected, print variant.
Why it stayed a Base Set quirk
The missing shadow was corrected before later WOTC-era sets like Jungle and Fossil went to print, so shadowless cards are reportedly unique to that one earliest slice of Base Set production. That narrow window is exactly why shadowless copies are treated as a distinct, tightly-bounded category by collectors and grading companies alike.
Frequently asked questions
What actually makes a card "shadowless"?
The absence of a drop shadow beside the artwork, corrected partway through Base Set's print run.
Are all shadowless cards also First Edition?
No, some early Unlimited prints are reportedly shadowless too — it's a separate detail.
Which sets have shadowless cards?
Reportedly Base Set only, since the shadow was added before later sets were printed.