#387 5¢ St. Lawrence Seaway, inverted centre, used with machine cancel, some original gum remaining and creased (as it went through the mail). CV $10,000.
2021 Greene Foundation certificate accompanies.
The famous “Seaway invert” was created during the two colour printing process, when the blue and red printing plates were not aligned, resulting in the fabulous error. Look at the stamp carefully and you will see the red and blue are in the opposite direction.
The normal stamp (both red and blue correctly aligned was issued June 26, 1959. In August, 1959 a Winnipeg office clerk purchased some stamps for his employer. The rare stamp was featured in national newspapers and a scavenger hunt ensued. Eventually additional sheets were found in Winnipeg and Picton. A total of four hundred stamps are reportedly discovered, with two sheets being returned to Ottawa.
The public interest was so high that mint copies were found and saved as valuable stamps. Used examples were mailed accidentally and are much scarcer, despite the mint catalogue value of $12,500.
Charles Verge wrote the definitive book on this error in 2009, a staggering 208 page examination of the error, its history and the famous dealers that owned the stamps. He provides a census of known examples both as mint, used and on cover.