It has to be struck thru a fragment. Mike Diamond will have to chime in on this one. You might try dropping him a PM. Nice find!
So would it be safe to say this coin was Struck Thru a Rotated Fragment? Sounds pretty cool, and pretty rare maybe?
While it could have been struck through a flake that detached from a struck cent, the clarity of the incuse lettering suggests it was more likely struck through a thin struck fragment. A thin piece of metal (possibly derived from a planchet) was situated between the reverse die and an overlying planchet. When the two elements were struck, the thin layer of metal molded itself to the recesses of the die face. The original planchet was ejected and a new one fed in. At some point the flake became dislodged, shifted position, and was struck into the fresh planchet. This generated an extensive set of incuse, normally-oriented design elements. I've seen many such errors, but this is a particularly nice one. The same effect can be seen on coins struck through dislodged and shifted late-stage die caps.