The only military objective on the islands was the city of Port Blair. The garrison consisted of a 300 man Sikh militia with 23 British officers, augmented in January 1942 by a Gurkha detachment of 4/12th Frontier Force Regiment of the 16th Indian Infantry Brigade. Following the fall of Rangoon on March 8, however, the British recognized that Port Blair had become impossible to defend, and on March 10 the Gurkhas were withdrawn to the Arakan peninsula.
The Invasion Force
The Japanese, seeking to secure their seaward flank, dispatched a force to seize the islands. The force was composed of the following units and ships: