The Battle of Jassin (also known as the Battle of Yasin and the Battle of Jassini) was a World War I battle that took place on 18– 19 January 1915 at Jassin on the German East African side of the border with British East Africa between a German Schutztruppe force and British and Indian troops. Jassin had been occupied by the British in order to secure the border between British East Africa and German territory, but was weakly defended by four companies of Indian troops—numbering a little over 300 men.