In interrogating prisoners the best results were obtained by employing Nisei, who obtained more information from prisoners when the latter were not subjected to questioning by an officer through an interpreter. Since most of the prisoners had been separated from their units for a considerable time and were seriously wounded, their information was sparse and generally out of date.
Captured documents were the most fruitful source of intelligence. Although the Japanese made a few attempts to destroy dog tags and other means of identification before going into battle, they were not too successful. The fact that General Krueger obtained information on the proposed ground offensive of the Japanese for the middle of November from papers found on the body of a Japanese officer was not an isolated incident. Many officers carried on their persons sets of orders and maps.
The Japanese received much of their information on the American order of battle from broadcasts emanating from San Francisco. At first, the Japanese on the island were unable to find out the American order of battle for Leyte but within a few days the Americans gratuitously furnished them the information. Said General Tomochika:
At the time of the landing, 35th Army Headquarters did not know the number or name of the American units which had landed ... but within a day headquarters learned.... We found out ... by tuning in on the San Francisco broadcasts; Japanese troops in the combat area were unable to determine their identity. From the same source, we later obtained information which was of considerable help in planning. In fact, that was the only way we could get information.... Information was always received through the San Francisco broadcast before reports from our front line units reached headquarters.... Since the information came much sooner from the American broadcast than from the Japanese communications, the Army Headquarters depended on the American broadcasts for much intelligence.[18]
Japanese Warfare
The 24th Division found the Japanese troops on Leyte to be better trained in combat and more skillful than those the division had encountered during the Hollandia-Tanahmerah Bay operation.[19] In general the Japanese fought a delaying action, and when forced to yield ground they would fall back to previously prepared positions. During a bombardment by American heavy weapons, the enemy troops would withdraw but when the fire lifted they would quickly reoccupy the vacated positions.[20]
The 21st Infantry was impressed with the Japanese “excellence in battle” on Breakneck Ridge. There were few instances of “reckless charges, needless sacrifices or failure to observe known tactical principles.” The most notable characteristics exhibited were the excellent fire discipline and the effective control of all arms. Without exception individual soldiers withheld their fire until it would have the greatest possible effect. The heaviest firing would generally start about 1530 and increase in intensity until about dark, the fire being accompanied by counterattacks from the front and on the flanks. These assaults usually came when the Americans’ energy and ammunition were at their lowest point during the day and when they would prevent proper consolidation of the front lines before dark.[21]
The Japanese employed reverse slope defense tactics with much skill and were successful in utilizing terrain for their defensive positions. Caves and other natural formations were exploited to the limit and positions were dug in deeply and expertly camouflaged. The Japanese frequently sacrificed fields of fire for cover and concealment, a fact which made it very difficult for the Americans to locate hostile positions.
Captured documents indicated that the Japanese attacks were generally well conceived but that there were not enough troops at the time of the assault. The documents also gave repeated indications that units either did not receive their orders or did not reach the appointed place on time. The Japanese employed two main types of attack. The first, which was similar to that employed by the Americans, utilized a base of fire from supporting weapons, followed by infantry fire and movement. This type of attack was not usually accompanied by artillery or mortar support. The other method consisted of a localized charge in which the Japanese by sheer force of numbers tried to crack the American lines. The heavy weapons fire of the Americans was nearly always able to break up both types of attack. Enemy forces, generally in small numbers, tried repeatedly to infiltrate through the American lines. The objectives were artillery pieces, supply dumps, and key installations. Rarely did they accomplish even minor damage.