Some of the most interesting errors also happen to be ones that are
faint, subtle, or camouflaged.
A deliciously stealthy mystery is found on a 1931 Ethiopia
25-matonas coin. It shows two obvious die alignment errors — a hammer
(reverse) die that was horizontally misaligned and strongly tilted.
These two errors often go together because when a die tilts down it
also tends to swing in, unless there is compensatory movement in the
opposite direction. In this case the hammer die shifted toward the
southeast and tilted down in the northwest. The hammer die’s elevated
pole failed to contact the southeast quadrant of the reverse face and
left unstruck the corresponding southwest quadrant of the obverse face
(a consequence of being struck in “medal rotation”). The planchet was
properly centered over the anvil die.
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Surprisingly, the southwest quadrant of the obverse face — which
faced the anvil die — is not entirely design-free. It displays two
faint, closely spaced rows of raised beads that roughly parallel the
coin’s edge and that are located approximately 3.5 millimeters in from
that edge. The inner row has nine beads while the outer row has four.
Like a set of parentheses, the curved line of beads lies directly
across from the unstruck crescent on the opposite face produced by the misalignment.
The size and shape of the beads corresponds to those normally
present just inside the obverse design rim. The obverse beads are
slightly larger than those on the reverse, as shown in a normal
It’s clear that before, during, or after the strike, the unstruck
southwest quadrant of the coin’s obverse face contacted the periphery
of the anvil die while the planchet was in an off-center position.
It’s not clear what provided the necessary resistance to the impact of
the anvil die. It stands to reason that any impact strong enough to
leave an impression would presumably require an equal and opposite
force (Newton’s third law of motion).
Over the years this column has presented an array of errors that
manage to sidestep this requirement without actually violating
Newtonian physics. These errors include extrusions strikes, stutter
strikes (three types), rim-restricted design duplication, and ejection
impact doubling. But none of the conditions associated with these
errors is present in the example under discussion.
The first step in our investigation is to see what the physical
evidence tells us about the circumstances surrounding this error.
Since the planchet was centered during the primary strike and
off-center when the extra beads were generated, it’s highly unlikely
that a single downstroke was responsible for every design element. The
isolated beads must therefore have been generated before or after the
The double row of beads implies either two closely spaced strikes or
a single jittery strike. It’s also possible that the beads were
impressed without the benefit of a downstroke at all. After all, there
are other means by which a planchet can make contact with a die (e.g.,
ejection impact doubling).
The two rows of beads are short and fade out at their ends. This
strongly suggests that the impact or impacts were delivered at an
angle. If a tilted hammer die was responsible, its downward-tilted
pole would have pointed toward the southeast quadrant of the reverse
face — a direction exactly opposite that of the tilted die error.
If the hammer die was inclined in this fashion, then it may have
been blocked by a second planchet overlying the planchet represented
by our featured coin. One would also have to assume that the hammer
die was not horizontally misaligned to any significant degree, since
the more medially positioned letters would have struck up instead of
Previous columns have documented rapid die oscillations
(side-to-side movements), rapid changes in die angulation, and rapid
changes in striking pressure. If the above scenario is correct, it
would imply that the double row of beads was generated while minimum
die clearance had momentarily increased to the thickness of two planchets.
In the end, we will never be sure what happened.