The Japanese 54th Division holding the Arakan was divided into two detachments holding the roads across the Arakan Hills leading from An and Taungup. The 82nd Division was asked to cross the Dalet Chaung and hilly terrain to approach the An Pass from the north west, while being supplied by air. The 1st and 4th (Nigerian) Brigades suffered heavy casualties in opening the routes to Kaw and Kyweguseik in late February. The 4th Brigade even lost two of its commanding officers. By March, the division captured Dalet Chaung and the strategic supply base of Tamandu, in coordination with Indian units.