U.S. ARMY FORCES FAR EAST -
8 December 1941
The Japanese plan was based on a detailed
knowledge of the Philippine Islands and a fairly accurate estimate of
American and Philippine forces. The Japanese were aware that the bulk of
the American and Philippine forces was on Luzon and that the U.S. Army
garrison had been increased since July 1941 from 12,000 to 22,000.
Eighty percent of the officers and 40 percent of the enlisted men were
thought to be Americans and the rest, Filipinos. American troops were
regarded as good soldiers, but inclined to deteriorate physically and
mentally in a tropical climate. The Filipino, though inured to the
tropics, had little endurance or sense of responsibility, the Japanese
believed, and was markedly inferior to the American as a soldier. The
American garrison was correctly supposed to be organized into one
division, an air unit, and a "fortress unit" (Harbor Defenses of Manila
and Subic Bays). The division was mistakenly thought to consist of two
infantry brigades, a field artillery brigade, and supporting services.
The Japanese knew that Mac Arthur also had one battalion of fifty-four
tanks-which was true at that time-and believed that there was also an
antitank battalion in the Islands. The harbor defenses were known to
consist of four coast artillery regiments, including one antiaircraft
The Japanese estimated that the American
air force in the Philippines was composed of one pursuit regiment of 108
planes, one bombardment regiment of about 38 planes, one pursuit
squadron of 27 planes, and two reconnaissance squadrons of 13 planes.
American aircraft were based on two major fields on Luzon, the Japanese
believed. They placed the pursuit group at Nichols Field, in the suburbs
of Manila, and the bombers at Clark Field. Other fields on Luzon were
thought to base a total of 20 planes. The Japanese placed 52 Navy patrol
and carrier-based fighter planes at Cavite and 18 PBY's at Olongapo.
The strength of the Philippine Army and
the Constabulary, the Japanese estimated, was 110,000 men. This
strength, they thought, would be increased to 125,000 by December. The
bulk of the Philippine Army, organized into ten divisions, was known to
consist mostly of infantry with only a few engineer and artillery units.
This army was considered very much inferior to the U.S. Regular Army in
equipment, training, and fighting qualities.
Though they had a good picture of the
defending force, Japanese knowledge of American defense plans was
faulty. They expected that the Philippine garrison would make its last
stand around Manila and when defeated there would scatter and be easily
mopped up. No preparation was made for an American withdrawal to the
Bataan peninsula. In October, at a meeting of the 14th Army
staff officers in Tokyo, Homma's chief of staff, Lt. Gen. Masami Maeda,
had raised the possibility of a withdrawal to Bataan. Despite his
protests, the subject was quickly dropped. Staff officers of the 48th
Division also claimed to have discussed the question of Bataan before
the division embarked at Formosa. The consensus then was that while
resistance could be expected before Manila and on Corregidor, Bataan
"being a simple, outlying position, would fall quickly."