At the turn of the century the eastern part of Africa had
been almost completely carved up into colonies of the four
Great Powers of Europe: France, Britain, Italy, and Germany.
The French concentrated in the west.  Their eastern presence
was limited to a strip of the Somali coast near the mouth of
the Red Sea.  The Italians held the rest of what is now
called Somalia, and had recently been beaten back from
Ethiopia by the Emperor Menelik II.  Far to the south lay
Portuguese Mozambique  The lands between: Kenya, Uganda,
Tanganyika, and some exotic islands, were fought over by
Germans and Britains in a conflict for dominance which would
seem not to be over yet.
Prior to the coming of the Europeans in the 15th century
the coast was part of a busy Indian Ocean trading system in
which goods moved from China and Indonesia through India,
Persia, Syria, and Arabia, then on to the African ports of
Djibouti, Mogadishu, Kilwa, and Zanzibar.  The slave trade
had been endemic there since the time of the Egyptian
pharaohs, and was a favored trade of the Arabs.  Of course
they also liked gold, and thus with the coming of Islam to
the East African coast there came also the first coins.
Hoards of early coins are not found in East Africa.  Only
the foreign traders used them, and the locals with whom they
traded.  The rest of the economy was carried by barter, the
major fiscal power lying in cattle, slaves, and salt, and
minor business being conducted in cowries.
Of course it's easy to get a cowrie in "uncirculated,"
usually from Philippines or Thailand.  It's much harder to
get a string of them, say, attributable to a time or place.
And there are horrible little copper coins from Kilwa and
some other places, hazily attributed to the 17th-18th-19th
centuries.  They're kind of like the coins of Harrar listed
in SCWC, larger, but worse looking.  They tend to be
elusive, with prices ranging from a couple of bucks to a
couple of hundred bucks for the same coin in the same grade
- just because nobody knows anything about them.
By the time the Europeans arrived in force the Indian
rupee was the standard silver coin in the region, and if
they wished to do intelligent business they must have their
own.  Thus we have in the 1890s the full weight rupien of
the German East Africa Company in Tanganyika and the pice of
the "East Africa Protectorate" (Kenya).  Of this latter type
the 1898 date is distinctly more common than the other two.
It is not an uncommon coin in XF, but it goes quick because
people need it for their type sets.
For reasons of convenience the British governors of the
East Africa and Uganda colonies decided to issue a joint
currency.  Using a format similar to the British West Africa
coins of the same period they issued minor coins with holes,
and in a nod to the rupee economy, silver 25 and 50¢ coins
weighing ¼ and ½ rupee respectively, but of an alloy debased
from the rupee standard.  The first minors included the ½¢
and 1¢ in aluminum, which metal turned out to be a poor
choice for that part of the world.  Most of them were
destroyed by the climate, and those which remain in
collector hands tend to be high grade and high priced.
Other coins of the series seem not to be especially
available, and tend to stay on want lists for a while.  The
rarities, such as the 1906 cent and 1919 50¢, are well known
and very seldom offered.  There is a proof set, but it does
not turn up.
In the aftermath of the German defeat in World War I
Tanganyika was given to Britain as a Trust Territory.  A
separate regional administration was established, and the
new government was invited to send representatives to the
East African High Commission and its subsidiary, the East
Africa Currency Board.  The "East Africa" series of coins
commenced in 1920.
One of the major problems of the Board was how to prevent
the drain of specie out of the colony to India.  Their
solution to the problem continued to be debasement.  In 1920
they put out a full weight but debased rupee imitation which
they called a florin (so they could say it wasn't a rupee).
This turned out to be too high a value for their purposes,
so the next year they changed to a shilling standard, 2/3
the weight of the florin (already down to only 54% of a
rupee's silver) and a breathtaking 1/3 of its value.  This
florin is the tough-but-obtainable type for the East Africa
series, turning up only occasionally in high grade at
exorbitant prices, and hardly ever in low grades.  None of
the 1920 minor companions are common either, and the 50¢ is
one of the well known rarities.
Shilling series types are all easily obtainable, though
the only coin available in bulk is the 1¢, which can be
found circulated in poundage.  Other denominations are
strictly one-at-a-time coins.  Except for a few dates in the
50s and 60s uncirculated minors are hard to find, while the
shillings are very tough in better than AU.
For some reason there seem to be an unusually large
number of 5 and 10¢ coins with center hole either misstruck
or missing entirely.  These coins exist from several mints
and dates, to the extent that cognoscenti are somewhat blase
about them and they get much lower prices than similar
errors from other countries (Denmark for instance).  A
dealer will typically try to get $10.00/+ for an offset
hole, $80.00/+ for no hole.
Proofs exist for many dates, but none are circulating in the