Bullseye (philately)

Bullseye, in philately, also called Socked on the nose (SON), refers to a cancellation of a postage stamp in which the postmark, typically a circle with the date and town name where mailed, has been applied centered on the stamp.

The colloquial expression "Socked on the nose" does not seem to be used in Europe: the terms Oblitération centrale in French or luxus in German are in common usage.

Austria introduced ca 1868 a set of cancellations of small diameter (< 20 mm), so that they could be seen entirely on all stamps.

[3] Some philatelists and collectors of cancellations have a special interest in bullseyes primarily because the date, time, and place the stamp was used, or postmarked, can be identified by the cancellation.

Because modern machine cancellations are normally arranged so that the wavy lines, slogans, or other killers are applied to the stamp, leaving the postmark clear, dealers and collectors desiring SONs will position the stamp on the cover so as to fall under the postmark.