Japanese Shipping. Note by Secretary

5. The situation clearly points to an enforced reduction in Japanese mobility from the Spring of 1943 onwards. This implies that the Japanese might have to change over to a strictly defensive policy, and endeavour to set up a defensive line held mainly by shore-based aircraft and naval forces operating under this cover, with which to inflict as much loss as possible on Allied attacking forces. The adoption of such a system would enable the Japanese to reduce the pool of shipping, held purely for military movements, to the level necessary for the quick movement of local reserves.