1981 S Penny-Clear Or Filled S?

clear

"Clear" and "Filled" does not really apply to the 1981 proof issues since both Ss are quite clear, it is the shape that matters. Type 1 and Type 2 is the more appropriate terminology. For 1979, the difference is quite obvious and the Type 1 is indeed filled(worn out mintmark punch) while the Type 2 is very distinct.

The problem is that the 1979 Type 2 "Clear" mintmark is actually the exact same mintmark as the 1981 Type 1 supposed "Filled" mintmark, hence the issue with the adjectival terminology. How can the same mintmark possibly be both Clear and Filled? In a rational world, it cannot be both but unfortunately the incorrect terminology has stubbornly persisted over time. For 1981, the Type 1 mintmark will have small rounded serifs and oval center loops while the Type 2 has large bulbous serifs and round center loops. Your coin would be a Type 2.

The Red Book is an odd duck. For the 1981-S cent, it has listed them as Filled and Clear, but for the 1981-S SBA, it has them listed First and Clear.