The following U.S. intelligence report on the Japanese tactical use of field wire was originally published in Tactical and Technical Trends, No. 47, June 1, 1944. [DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]

JAPANESE FIELD WIRE Preliminary reports from the field disclose the following information on the tactical use of wire by the Japanese army. Two samples of Japanese field wire, mentioned below, used in the northern Burma area, leads to some interesting findings about the composition and properties of this wire. a. Tactical The wire is ordinarily used in a single conductor ground return circuit. The conductors are used only in extreme cases where security is of utmost importance. The wire is usually laid above ground on bushes or branches, and the same wire is used for either telephone or telegraph channels. The supply of field wire in the Japanese army appears to be quite limited. Wire is very seldom abandoned even at the expense of abandoning other valuable equipment. Often in new positions the wire may be old or well used. b. Physical Characteristics The two samples of field wire were somewhat similar in general appearance though a marked difference appeared in their physical and electrical characteristics, Sample No. 1 consisted of three copper and four steel strands twisted together. The insulation was black rubber approximately 0.030 inches in thickness. The outer covering was bright yellow, impregnated cotton braid. The outside diameter of the wire was approximately 0.100 inches and the weight of the 59-foot sample was seven ounces or about 39 pounds per mile. This wire was somewhat similar to one conductor of the American type W-110 B wire. Sample No. 2 consisted of seven steel strands and one heavy copper strand twisted. The insulation was black rubber approximately 0.020 inches in thickness and the outer covering was a dull red waxed cotton braid. The outside diameter was approximately the same as that of sample No. 1. c. Electrical Characteristics The direct current resistance of sample No. 1 was 1.3 ohms for the 59-foot length or approximately 22 ohms per 1,000 linear feet. The resistance of the second sample could not be measured since the length of the section was only 4 feet 10 inches. d. Conclusions Sample No. 1 appeared to be the standard Japanese field wire in use in Burma and corresponds in characteristics to one conductor of American Type W-110 B field wire. It was somewhat lighter but had a greater direct current resistance. The black rubber insulation appeared to be of inferior quality. Sample No. 2 appeared to be a form of assault wire; however it was much heavier and much more bulky than the comparable American type. The insulation of this wire appeared to be very poor. Due to its great tensile strength, this wire may be intended for use on poles or tied in the air between trees. Either of these wires, if captured in quantity, could be used with American field telephone and telegraph sets, either as single conductor, ground return, or two conductors could be laid in parallel. Used in this way the wire is probably inferior to American wire in transmission characteristics.

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