Z Force did this sending intelligence units into Japanese held territory that then relayed the information back to the headquarters of the Fourteenth Army by radio.
[1] The intelligence units that went behind enemy lines were made up of expatriates and of Burmese from the Chin, Kachin and Karen peoples.
The expatriates, who had worked in Burma before the war and were familiar with the jungle, were all commissioned as officers from captain to colonel.
The "highly dangerous mission in a war noted for its ferocity and bestiality" were carried out in some of the most difficult jungle terrain in the world.
[1] During the campaign Z force personnel were awarded one CBE, two DSOs, four OBEs, four MBEs, seventeen MCs with bars to two, and sixteen Burma Gallantry Medals.