I wanted to return to this topic after some time because I think there remain some very good questions here, in particular Stephen's queries regarding trade during the Mahdiyya.
I just happened to have been doing some reading on the topic recently. According to Zeleza's
A Modern Economic History of Africa: The Nineteenth Century trade was considerably disrupted during the Mahdiyya.
The British and Egyptian administration had declared a complete prohibition on trading with the new state for fairly obvious reasons. Meanwhile two wars with Ethiopia had greatly diminished trade via that route - which had been an important route to Massawa, the great port city on what is now the Eritrean coast.
The Mahdiyya's administration also restricted what goods could be traded, such as tobacco and restricted trade and traders from countries considered to be inhabited by unbelievers.
It would certainly seem plausible to say then that the traffic in blades was likely greatly reduced by the normal routes. Effecting the flow of German trade blades into the region. Of course the routes to the west would still have been open via Kano through Bornu.
However I believe the greatest number of blades passed through Egypt via Cairo. Burckhardt in
Travels in Nubia in 1822 gives a figure of 3000 Solingen blades annually passing through Cairo and being sold south by traders (as a side note, this is certainly a more reasonable figure than Barth's 50,000 estimate in Kano!).
This would have been cut off during the Mahdiyya and alternative sources would doubtless have been sought as the new state was in desperate need of fresh warriors, evidenced by the fact that the previously lucrative slave trade was curtailed for males over the age of 7.
There is nothing to indicate this sword is different because of the above circumstances, but it is an interesting thought.
