William and Mary (1689-1694), Halfcrown, 1689, second shield, caul only frosted, so-called ‘inverted f’ in gvlielmvs, edge primo (ESC 509b; S 3435). Some detail of hair weak, otherwise about very fine and toned (£150-200)

The illusion of an ‘inverted f’ is nothing more than the result of a partially filled top bar to the e in the king’s name, almost certainly caused by the die being clogged with dirt or detritus