Auction 333-341 Nigeria, Cameroon, Sudan & Worldwide Postal History - Day 4

Biafra 1962: Nigeria Benin Mask 6 d. air letter form, the word "NIGERIA" crossed through and replaced beneath with manuscript "BIAFRA", used from Aba to Dublin, Ireland, dated 27 November 1969, franked with 1969 2nd Anniversary of Independence 2 s. 6 d, cancelled by a "ABA" circular datestamp. To the reverse a "LIBREVILLE GABON" circular transit datestamp in black dated 29 December 1969. An unusual and scarce usage.
Reference: The Postal Stationery of Nigeria, by Peter Hørlyck, illustrated pg. 297.