More progress was happily made during the winter in still more distant spheres, although the conquest of German colonies was regarded by the pure strategist as belonging to the illegitimate and divergent rather than to the legitimate and subsidiary type of military operation. Policy may, however, outweigh strategy, and the circumstance that the victor only retains as the price of peace his conquests, or part of them, made in war, extenuates if it does not justify divergent operations. They were divergent enterprises which gave us India, Canada, and the Cape of Good Hope; and assuredly the defeat of Germany on the Western front would not alone have brought German colonies under the sceptre of a League of Nations. Even from the point of view of a strategy limited to Central Europe these operations had their value; for they enlisted against the common foe forces which would certainly not have been employed had we merely stood on the defensive in the overseas Dominions, and when their work was done in distant parts these forces gravitated towards the centre with a weight which would have grown more crushing had resistance been prolonged. Only surrender by the enemy stayed Allenby's and Marshall's Oriental hosts in Asia and anticipated the arrival on the Western front of further aid from Africa. A blow at the heart may be the normal strategy, but it is not the only nor always the best means of dealing with an antagonist clad in a breastplate of steel.
The scene of the least successful of these colonial wars was still East Africa. The reverse of Tanga in November was followed by another at Jassin on 19 January, and at the end of the winter the Germans could claim that their territory was clear of our troops while several German detachments were in ours; but we had seized the island of Mafia off the mouth of the Rufigi and declared a blockade of the German East African coast. On the other side of the continent we made steady progress in reducing the vast territory of the Cameroons; but the success of the season was Botha's conquest of German South-West Africa. The last remnants of the rebellion under Maritz and Kemp were stamped out at Upington on 3 February, and on 14 January Swakopmund was captured from the sea. Botha selected that as his base, while Smuts directed three columns farther south. The first advanced on the capital Windhoek from Luderitz Bay, the second from Warmbad near the Orange River, and the third from Kimberley. The second, under Van Deventer, had the heaviest work, but the fighting was not as a rule severe. The campaign was a triumph of forethought, strategy, and organization which left the Germans no choice but a series of retirements, culminating in the surrender of Windhoek on 12 May, and the capitulation of the entire remaining German forces at Grootfontein on 9 July.