In order to realize increased production of aircraft, raw materials had to be conveyed by ship from overseas.
The personnel charged with Army shipping operations felt that the prerequisite for victory in the Pacific War was safeguarding surface transportation.
They argued strongly that the Combined Fleet should devote its main strength to convoy work, like the British Navy had done during World War I.
Efforts should meanwhile be made to reinforce air power by making surface transportation secure-thus accelerating aircraft production, in turn.
On March 17, 1944, a Joint Army-Navy Conference was held in the presence of the Emperor, to study methods of meeting the shipping-loss problem.
The conference took 2 hours, and the Army finally decided to adopt certain major measures: War Minister Hideki Tōjō had good reasons for adhering to his opinion during the arguments with the Army High Command about the problem of requisitioning operational shipping space.
In order to devise efficient radar weapons for practical use as soon as possible, however, both the Army and the Navy should have pooled their research facilities; but here again the serious rivalry between the armed services stood in the way.
Among those concerned with Army operations, incidentally, not a few were of the opinion that the inferiority of anti-submarine radar devices was a cause for Japan's defeat.
In other words, the country lost out in the logistical sense because of great shipping losses, which were in turn directly attributable to the radar weaknesses.
Accompanying the decline in maritime transportation potential, the Army began to seek an improvement in the movement capacity of the railroads on the Asiatic Continent-to make up for deficiencies at sea.