perf 12½, no wmk
Printed at the Mint, Lisbon.
|Overprinted locally on the stamps of Cape Verde Islands|
|5 reis black||1||1||1||1||
|20r deep bistre||2||3||3||3||
|25r deep rose||3||4||4||4||
|Mozambique error †||4a||5a||5 I F A||5a||
|200r deep orange||6||8||8||8||
The catalogues note that forgeries of the issues are common and that there were official reprints in 1885 and 1905, both perf 13½
|1881 Sc4a SG5s Mi? YT5a Mink5t|
† The Mozambique error is a delight. Position 18 on the plate of Cape Verde Islands 40 reis blue was actually a Mozambique ("MOÇAMBIQUE") stamp and the error was perpetuated through subsequent overprinted issues until 1885. All the stamps in this set are expensive, but the 40r error is priced in 1984 by Gibbons  at £5,000. By 2008, Scott  values it at $16,500/$15,250.
The only image of the error found to date is from a 1954 edition of Life magazine in a 15-page article entitled Stamp Album Worth $1,000,000.
to a copy of the magazine in Google Books, from which the image was taken showing a valuation of $2,000.
A copy of the magazine has been acquired on eBay (Sept. 2016), to be shipped to the UK at considerable expense, and it is hoped that a better image will be provided in due course.
Minkus  priced the stamp at $7,000 in 1970; Yvert & Tellier  at €20,000 in 2010.
Looking at more recent catalogues:
£32,000 / £30,000
$16,500 / $15,250
Portuguese Guinea became a dependency of the Cape Verde Islands in 1877 and used its stamps until 1880. In March 1879 it became a separate colony and issued its own stamps (albeit overprints of Cape Verde stamps at first) from 1881.
In January 1963 the PAIGC (Partido Africano da Independência da Guiné e Cabo Verde) mounted an armed rebellion against colonial rule. More than ten years later in September 1973 the Republic of Guinea-Bissau was declared, claiming posession of two-thirds of the country and this was recognised by Portugal in September 1974.
10th September 1974
|1974 Sc345 SG426|
Originally a Portuguese colony, in January 1963 the PAIGC (Partido Africano da Independência da Guiné e Cabo Verde) mounted an armed rebellion against colonial rule. More than ten years later in September 1973 the Republic of Guinea-Bissau was declared, claiming posession of two-thirds of the country and this was recognised by Portugal in September 1974.