Despite the fact that a majority of Italian officers in WW2 were sub-standard, the commander in East Africa – Duke D’Aosta, was a very good, intelligent, young leader. At his disposal, to defend East Africa, he had 288,000 men, 200,000 of these were colonial troops (Eritreans being very trustworthy, Somalis semi-trustworthy, and Ethiopians of dubious trustworthiness).
In the beginning of the campaign, the Italians went on the offensive, at first surprising the British in Sudan and Kenya, but making only small gains. This action, however, proved to be only a feint, as D’Aosta then struck British Somaliland. For this offensive, the Italians (led by Major-General DeSimone) gathered 23 battalions of Eritreans and Somalis, 2 battalions of Blackshirts, 1 battalion of Sardinian Grenadiers, plus artillery, some tanks, and horse cavalry in support. The Italians moved forward well, harassed only by sniper fire from the British Somaliland Camel Corps. At the same time, the Italian “Harar” Division attacked Somaliland through the Tug Argan Pass, and after 3 days punched their way through it. British Somaliland was now evacuated by sea. 465 Italian troops died and 1530 were wounded in this offensive.
In the Sudan, meanwhile, the Italian 2nd Colonial Division was fighting off attacks by British Indian troops. This would continue for the next 5 months.
Despite these early successes, D’Aosta knew his situation was grim. He did not have the resources for a major offensive, and he new that his troops had only fought against outnumbered, 2nd and 3rd rate British troops. It was only a matter of time before the British decided to send some “real” troops to the theatre, and crush him. However, D’Aosta decided that he would fight as long and hard as possible, and if he could tie down a major Allied force for several months, his defeat would not be in vain.
D’Aosta now divided his command into 4 sectors. Major-General DeSimone would hold Somaliland with 10 colonial brigades. General Guglielmo Nasi would protect western Ethiopia with 4 colonial brigades. General Frusci, with 3 colonial divisions, 6 colonial brigades and 5 Blackshirt Battalions would defend Eritrea and Gondar. The 4th sector was central Ethiopia, which the Duke would hold himself with his best troops – the ” Africa” Colonial Division, and the all Italian “Savoia” Grenadier Division.
The first British counter-attack happened in December, 1940, when the Indian 10th Brigade re-took Gallabat, in Sudan, from the Italian 27th Colonial Battalion. However, when the Indians attempted to follow-up this action by crossing into Ethiopia, they were defeated at Metemma by colonial troops and Blackshirts under Lt.Col. Castagnola.
After this embarrassment, the British built up their troops in the Sudan. They formed a Corps, consisting of 2 Indian Divisions (the 4th and 5th Divisions). These divisions were actually 1/3 Indian, 1/3 Gurkha, and 1/3 British infantry, with the artillery, technical positions and officer corps being mostly British.
On January 18, 1941, the British moved forward, only to find Kassala, in Italian occupied Sudan, abandoned by the Italians. The Italians had fallen back to Keru in Eritrea, and the Indian divisions attacked them here. The goal of this offensive was to take the Italian naval base at Massawa.
Keru was quickly surrounded, however, the Italian 41st (Eritrean) Colonial Brigade managed to break out and withdraw to Agordat. 900 Italians and colonial troops were lost at Keru, however.
At Agordat, the retreating Eritreans and Italians joined the garrison, that consisted of the 4th Colonial Division, a battalion of Blackshirts, some artillery and rear-echelon units, as well as 150 German seamen (Compagnia AutoCarrata Tedesca), that had been trapped in East Africa. All told, 12,000 men would defend Agordat.
The town was quickly surrounded, and after 3 days of fighting, the garrison commander ordered a break-out, finding his position untenable. The break-out was successful, but most of the Italian heavy equipment had to be left behind.
At the same time, the Indian 5th Division was attacking Barentu, that was defended by 6,000 men of the 2nd Colonial Division. Here, too, a break-out was possible; and the 2 retreating columns of remnants now converged on Keren, where they joined the Italian 11th Grenadier Regiment of the Savoia Division in its defense.
On February 3rd, the Allies attacked Keren. Attached to the 4th Indian Division was a Palestinian Commando Detachment. The Italians and their colonial troops fought well, and all attacks were beat off.
Not as successful were the Italians in Somalia, where, at Afmadu, the Italian Somaliland troops deserted en-masse in the face of an attack by the British 12th (Black) African Division. Further attacks by the British 24th Gold Coast Brigade and the 1st South African (White) Division crossed the Jaba River and took Gobaen and Kismayu. A counter-attack by the Italians floundered when most of the Italian Somali troops refused to fight, or simply disappeared. Allied warships and air force assisted the offensive with bombing, to which the Italians had no reply. Mogadishu was abandoned on the 25th of February, and the Italians conceded all of Somalia, attempting to form a defensive line a Jijiga, Ethiopia.
This defensive line was manned by mostly Ethiopians and Italians, as the Somali colonial troops had, for all intents and purposes, seized to exist. On March 18, Nigerian infantry, supported by British artillery, attacked the line, and within a few days had pushed the Italians back to the Babile Pass.
D’Aosta’s army was now quickly disappearing, as not only were the colonial troops deserting in droves, the Italian troops were disappearing too. Some of these Italians were colonists whose homes were in Africa, and whose wives and children were being threatened by marauding native deserters – they deserted in order to go home and protect their families.
By the 24th of March, the Allies had breached the Babile Pass, and by the 26th had crossed the Bisidimo River.
The Italians abandoned Harar and retreated to Dire Dawa. South African troops entering the city had to protect Italian civilians from rioting Ethiopians.
The town of Keren had held out until the 27th of March, when a massive tank attack finally broke the back of the stubborn Eritrean and Italian defenders. The town had held-out for 57 days, and had inflicted casualties of 3,835 on the Allies. The bulk of the defenders did not surrender, however, but broke out and retreated southwards, towards Massawa and Asmara, chased by the 4th and 5th Indian Divisions, and a Free French Brigade.
On April 1, 1941, Asmara fell to Free French Foreign Legion troops.
On April 5, 1941, D’Aosta declared the Ethiopian capital, Addis Ababa, to be open, and withdrew to Dessye.
On April 8, 1941, Massawa fell to Indian troops.
The Italian East Africa Fleet attempted to escape, but after losing 4 Destroyers to air attacks , Admiral Bonetti surrendered his remaining ships.
On April 18, 1941, D’Aosta formed a defensive line at Kombolchia with his reliable, Eritrean “Africa” Division.  A first attack by South African troops was repelled, but a counter-attack by the Eritreans was a disaster. Over the course of the next few days, the Italians held out against massed attacks by South African troops and Ethiopians that were now fighting on the British side. By sheer weight of numbers, the stubborn defenders were overwhelmed, and forced to retreat yet again.
D’Aosta’s survivors gathered at Amba Alagi. They numbered only 7,000 men, and 40 artillery pieces.
On April 29, 1941, these remnants came under attack by Allied forces, including Ethiopians now fighting against the Italians that outnumbered the defenders 5 to 1. However, D’Aosta’s men fought bravely, and held out for 3 weeks. During the siege, several Italian outposts were overrun by swarms of Ethiopians, who then noisily tortured any captured Italians to death. On May 19, 1941, D’Aosta surrendered his immediate command to the British (400 Eritreans and 4,400 Italians). However, this was not the end of the campaign, as this surrender did not include any Italian troops resisting elsewhere.
Other Italian troops surrendered as follows:
-the Italian 21st, 25th and 101st Colonial Divisions (Somali), under Generals Baccari and Liberati, surrender at Soddu, Ethiopia, at the end of May, 1941;
-the Italian 24th Colonial Division surrenders at Jimmu in early July, 1941;
-General Gazzera, with a mobile column of 5,000 Italians and 2,000 Ethiopians, surrenders to a Belgian Congolese unit and a Nigerian Brigade at Demli on July 3, 1941;
-at Addis Dera, Colonel Maraventano and 5,000 men, mostly colonial troops, is surrounded by tens of thousands of fanatical Ethiopian tribesman, joined by deserting Ethiopian colonial troops. Many Italians were literally sliced to pieces by the tribesmen. The saving grace for Maraventano was the arrival of a Sudanese battalion, led by a British officer. Upon guaranteeing prisoner safety, Maraventano’s troops surrender to this unit;
-Italian garrisons at Kulkaber, Debra Tabor, Chilga, and Wolchefit Pass all surrender between June and November, 1941. The garrisons at Wolchefit Pass and Kulkaber had fought especially well till their capitulation, causing well over 1,000 Allied casualties each, and giving up only after running out of food;
-On November 27, General Nasi orders the immediate surrender of all remaining Italian units in East Africa. He had held up for over 6 months since taking command from Duke D’Aosta, outnumbered 3 and even 4 to 1.
In conclusion, General Duke D’Aosta, and his worthy second in command, General Nasi, had known the outcome of the war in east Africa ever since it began, however, like true soldiers, they fought on for 17 months, tying down no less than 6 divisions, that the Allies could have desperately used elsewhere. One can only imagine what could have become of the Italian Army, had the leadership of these officers been the norm, rather than the exception.
I regret to read some mistakes about the Italian war in AOI ( Italian East Africa during the 1940-1941 campaign, not to mention the next two years of resistance by many thousands of men and women, Italian, Eritreans and Ethiopians; ref. Enrico Cernuschi, La resistenza sconosciuta in Africa Orientale, Rivista Storica, dicembre 1994. Available by Rivista Italiana Difesa, RID in the web).
 It’s difficult to understand what’s mean “sub standard officer”. The level of the Regio Esercito officers and petty officers was a modest one, I agree: too many six months machine made junior officers, too many old, dismissed officers of the last World War without the necessary experience but only, sometimes, a gallant past as young lieutenants twenty years ago which is not the best credit for a sudden major or Lt. Colonel, Staff generals at H.Q. quite debatable but, in AOI, there was, instead, quite an high proportion of professionals and the consequences, as is possible to read in the digest at the origin of this mine, were clear as the comparative performance was better than in the Mediterranean. As a matter of fact professionals only could lead the native troops of the Regio Corpo Truppe Coloniali; it was a difficult job not fit for amateurs.
 The history of the German Company in AOI is fully described in the following article: Piero Crociani, A.O.I. 1940; un reparto tedesco nel regio Esercito, STORIA militare, May 1995 (You may look for it in the TUTTOSTORIA web).
 The Italian Destroyers were not escaping, but tried to do, with the very last oil available carried from Assab to Massawa by the Oiler Niobe, a last attack against Port Sudan after a previous tentative towards Suez sailing along the Arabia coast.
 Admiral Bonetti did not surrender his ships. They were scuttled (see, for details, Warship International, n.1/1994). For the history of that forgotten naval campaign see Enrico Cernuschi: La rivalità italiana nel Mar Rosso, STORIA militare, Gennaio 1995 and Febbraio 1995; Enrico Cernuschi La rivalità anglo-italiana nell’oceano indiano, luglio 1996 e agosto 1996.
 The Division Africa was not an Eritrean unit but an Italian one, formed by colonials who were not yet in the blackshirt Milizia Coloniale.
The article seems to be written from a desire to put the best possible gloss on the Italian performance in East Africa. However, in doing so it overstates the case by using such terms a “massive tank attack” and “massed attacks by South African troops” to give the impression that the odds were more heavily stacked against the Italians than was in fact the case. In fact, sheer numbers were almost always on their side. There could be no massive tank attacks because the British did not have massive numbers of tanks in the theatre, and I am aware of nothing so crude as massed attacks being launched by the South Africans.
Looking more widely, the Italian performance in East Africa in 1940-41 does not look particularly poor by comparison with the British in Malaya and the Americans in the Philippines in 1941-42. However, it should not be built up into an epic it was not, either.
The only front where is possible to speak about massed attacks with the aide of armoured units (modest on the European scale, quite important in that theatre of war, is along the Giuba river, Somaliland. There the Italian cordon line, without any other strong point along the flat and desert Ogaden region before the Marda Pass, 800 miles far, was broken, at least, by the West and East Africa brigades employed in Great War style on February 1941. Once the hole was punctured all was lost on the southern front.
No Sudanese campaign was possible on summer 1940. The rainy season starts there in May and ends in September. During the “Habub” time the very idea to cross the region from Cassala (which was conquered by the Italian Native Cavalry in July 1940 like a Wild West operation of the 7th Cavalry) to Atbara, not to mention Khartoum, was a logistic absurdity. In October Rome had asked an offensive towards Port Sudan but the 5th Indian Division had yet arrived in September and so only a raid by a “banda” (irregular group) led by Colonel Rolle was accomplished in the Sudanese region. It had a certain propaganda and deterrent effect, according some British sources, but no strategic consequence, of course.