The first phase of the campaign, which lasted from June 1940 to December 1940, saw the AOI grow progressively thanks to various territorial gains :
- Sudan : occupation of border posts of Kassala, Gallabat and Kurmuk opening the road in the direction of Khartoum and, indirectly, of Egypt ;
- Capture of British Somaliland giving a territorial unit to the Empire and an additional opening on the Red Sea ;
- Kenya : conquest of Moyale giving access to Nairobi, and by extension to the British possessions of East Africa.
However, this period will also see a progressive weakening of the Italian troops and in particular of a Regia Aeronautica in a war of attrition. While, at the same time the Commonwealth ground troops, RAF and SAAF will continually grow up to be able to take the offensive.
For its part, the British strategy is relatively simple. The first is to ensure the protection of the borders, mainly of the Sudan, while waiting for a reinforcement of troops. During this period, the use of RAF and a disinformation campaign must be put in place in order to discourage the Italians from any offensive.
After the arrival of the reinforcements, towards the end of 1940 / beginning of 1941, an offensive was to be launched on the northern front towards Eritrea and on the south towards Italian Somalia in order to occupy the coasts, eliminate the threat to the Red Sea, and exhaust Regia Aeronautica. Once this objective has been achieved, as well as the neutralization of Italian nuisances against maritime and transport routes, a possible invasion of Ethiopia could be envisaged.
The main task is therefore to prevent any enemy attack on Sudan (and, indirectly, Egypt) and disruption in the Red Sea. The total neutralization of AOI is only secondary.