Germany still has forces at large in its West African colony of Kamerun. Some of these are besieged at Mora in the north of the country. Forces based at Garua have retained their freedom of action and recently launched a minor invasion of British Nigeria. Although defeated, the German invasion has angered the British: it is simply unacceptable for enemy forces to be invading its colonies. The German base in Garua must be taken.
Now an Allied force (mainly British, but with some assistance from the French, including heavy artillery) has reached the environs of Garua. The Germans have fortified their base and stockpiled food and ammunition in preparation for a long siege. But the British want things over in a much shorter timescale. They dig trenches opposite the weakest part of Garua’s defences and then begin to batter them with the French guns. At night the Allies work to further undermine the enemy’s defences by digging their trenches closer and closer to the German lines.
map of German Kamerun (Wikipedia)
German troops man the defences of Garua (Wikipedia)