Action Comics #223 Error Variant:
Misnumbered #233

DC Comics (National Comics), published Date: December 1956.

Action Comics #223 was distributed in Fall/Autumn 1956, with a published date of Dec 1956. The main story is entitled "The First Superman of Krypton", from a script by Edmond Hamilton, with Ka-El discovering that his father, realizing the destruction of Krypton was imminent, had experimented with a simulated yellow sun environment and had realized that Kryptonians would possess supreme power on Earth.

Sometime during the print run for #232 it was realized that the early copies were misnumbered as #233; this was then corrected and the rest were printed with the correct numbering. Below are cover fragments showing the corrected #223, the erroneously numbered #223 (#233) and the pink cover from the much later #233 from 1957.

The error only seems to be on the cover of the comic: the interiors appear to be identical, including the indicia (below).

CGC have sensibly separated the error copies as a variant of #223, in their census, with the copies numbered #233 categorized as "Misnumbered Variant" (one single 8.0 in the census around mid October 2016); hopefully they can do the same with the Superman #75 Error Variant (that was also misnumbered) at some stage.

It is unknown how many of the misnumbered error variants were printed, distributed or exist today but they certainly seem to be hard to get hold of and very high grade copies could go for a small fortune.