Franz,
Here's what seems to happen with a die clash. The obv die has the large central
bust, and the rev die has some more varied design. You can see that the result of striking a coin after the die clash is that the
reverse die will impart on the
flan not only the raised
reverse design, but also a sunken (
incuse)
obverse design. It's not all all intuitive until you see the diagram (I just came up with this the other day trying to figure it out for myself).
You can see from this drawing that with a die clash the portion of the raised design over the
incuse area may actually appear
enhanced (i.e. unaffected) relative to the rest of the coin, whereas for a restruck
brockage I think the opposite would occur - the
incuse area of the
flan would be less likely to fully meet the die on the second strike, and the raised design in that
area is likely to be weak.
It also seems that it's the
bust that will show up most clearly on a die clash since it's a large mostly/wholly
incuse area on the die, surrounded by the higher mostly uncut
legend area which will therefore hit the other die first leaving an imprint of the
bust. With a more varied design such as a typical
reverse design, there's not typically going to be such a large differerence in the distribution of contact areas when the dies meet, and therefore less of an imprint/effect (the force is more evenly distributed).
Ben