The KM#13.1 variety distinguishes this issue from the later 13.2, which followed Nigeria's broader coinage reforms of the mid-1990s as the country cycled through successive military governments, each inheriting an economy strangled by oil dependency and structural adjustment pressures from the IMF. Nickel-plated steel replaced the earlier cupro-nickel composition as a cost-cutting measure, a change that makes these pieces prone to edge corrosion where the plating is breached.
The KM#13.1 variety distinguishes this issue from the later 13.2, which followed Nigeria's broader coinage reforms of the mid-1990s as the country cycled through successive military governments, each inheriting an economy strangled by oil dependency and structural adjustment pressures from the IMF. Nickel-plated steel replaced the earlier cupro-nickel composition as a cost-cutting measure, a change that makes these pieces prone to edge corrosion where the plating is breached.