I thought I will follow up on my brunei stamp history to correct my earlier posting on Brunei stamp. In my previous posting I noted that "...it wasn't until 1952 before the government issued the first Brunei stamps with the picture of His Majesty Sultan Haji Omar Ali Saiffudien, the 28th Sultan thus beginning the modern era of Brunei stamps..." However I have since discovered that this is not so. I found two sets of stamps which were among the first to be slightly different from the designs of 1895, 1906 and 1924.
The Brunei philatelic history is relatively short. The first set of stamps were released in 1895 called the Brunei Locals. The second set of stamps were those of the Labuan Colony overprinted with the word "Brunei" issued in 1906 because the Brunei stamps were 'lost' in Singapore. It wasn't until 1907 when the Brunei 'River Type' stamps arrived. In 1924, a new design with a view of the Kampung Ayer was released. (All the stamps can be viewed in that earlier posting.) During the war, the Brunei stamps were overprinted with the Japanese characters.
The first slightly different stamps were those that was scheduled to commemorate the Sultan Ahmad Tajuddin's Silver Jubilee to be released on 20th September 1949 but was not released until the 22nd as the two days prior were declared to be public holidays. The stamps were recess printed by De La Rue in denominations of 8 cents, 25 cents and 50 cents. The design is similar to the 1924 stamps but with the potrait of Sultan Ahmad Tajuddin, the 27th Sultan of Brunei. That was the first time a ruling monarch of Brunei appeared on the stamps of Brunei. Three years later, in 1952, Sultan Omar Ali Saiffuddien became the 28th Sultan and new stamps were issued.
Another release in 1949 was to commemorate that of the 75th Anniversary of the Universal Postal Union.
So far these are the only two sets that I know of released before the Sultan Omar Ali Saifuddien's definitive stamps that were issued in 1952 onwards. If there are other sets, do let me know.