Text of a U.S. intelligence report on the Japanese use of smoke, from the Intelligence Bulletin, July 1945. The illustrations in the original have not been included. [Editor's Note: The following article is wartime information on enemy weapons and tactics published for Allied soldiers. More accurate data on Japanese weapons and tactics is available in postwar publications.]

 

SMOKE IN THE ATTACK A STUDY BY THE KWANTUNG ARMY During large-scale maneuvers in Manchuria, the Kwantung Army—one of the enemy's most highly trained and experienced units—experimented elaborately with the use of smoke in offensive operations. When the air had cleared, and the last blank round had been fired, Jap officer observers seemed surprised to find that their experiment had succeeded beyond their first expectations. Smoke as a weapon has not been used extensively by the Japanese, although they are fully equipped for this type of warfare. Apparently they held the Manchurian maneuvers to study the effectiveness of smoke candles used to conceal the movements of front-line troops, and the ability of artillery to blind hostile observation posts with well-placed smoke shells. However, besides blinding the defending troops, and making it impossible for artillery and heavy weapons to fire anything but direct fire, the smoke produced a strange psychological effect among the "enemy" under attack. The smoke created a feeling of isolation and uneasiness among the defenders. The Japanese reported that distances seemed enlarged, and the movements of the attacking foot troops appeared elusive and "created illusions in the defender". The normal rate of defensive fire was decreased 25 to 50 percent, and it was discovered that troops subjected to heavy smoke for a period of 30 minutes or longer were forced to use their gas masks. Soldiers who did not wear their masks suffered headaches, sneezing, vomiting, sore throats, and respiratory ailments. A result of the maneuvers was a series of recommendations for the employment of smoke in offensive operations. The Kwantung Japs concluded that the proper use of smoke on a large scale enabled infantrymen to come to grips with a defending enemy, and to penetrate his positions, against a minimum of defensive fire. A critique of the maneuver recommended that in conducting such attacks, troops should take advantage of the range and accuracy of artillery to lay smoke concentrations on the enemy's lines. Besides smoke, mortar fire should be used to harass lines of communication and command posts, and to neutralize observation posts and defensive weapons positions—particularly those which could deliver flanking fire into the attacking troops. At the same time, the infantry should lay its own smoke screen, the critique pointed out. It was mentioned that infantry might find it necessary to lay smoke in depth through a portion of the enemy's lines, or to lay a strong blinding concentration upon a specific part of his defenses. Presumably, smoke mortars and smoke grenade dischargers would be used, in addition to smoke pots and candles. Following the thought emphasized in Japanese training manuals, the critique touched on the necessity for studying and exploiting wind conditions, the advantages of having several plans for discharging and distributing smoke, and the benefits of "following to the letter" any plan selected. The Japanese evidently decided that actual assault operations should be conducted under independent battalion control, or even company control, with the battalion or company commander maintaining artillery coordination and establishing the phase lines. Before such an attack, the battalion or company would be divided into small task units, and each unit assigned a specific weapon position or strongpoint to attack. Similarly, it was recommended that a special task unit be organized to operate under the direct command of the battalion or company commander. Such a special unit, if not committed to reducing a particularly critical strongpoint, would then be used to oppose any unanticipated weapon positions or troop concentrations that might be encountered once the attack was under way. If a Japanese battalion or company were to conduct a smoke-infantry attack as outlined by the Kwantung observers, the attacking force would be divided into two or more waves before the assault. The first wave, composed of the task units, would engage designated hostile weapons positions. If these strongpoints were not reduced by the time the second wave reached the enemy lines, the second wave would leapfrog through the wave of task units and force a penetration to the enemy rear. Occasionally a "mop-up unit" might follow the second-wave troops, and take over the mission of cleaning out isolated strongpoints left behind by the momentum of the attack, but still active. Heavy weapons also will follow close on the heels of the attacking waves of infantry. Whenever possible, such an attack will strike from the flank, with the attacking troops making the most of the concealment provided by the smoke. As the defender's final protective line of fire is approached, the attacking troops will advance by rushes and by crawling. Every effort will be made to discover and use defiladed terrain features, or other soft spots in the defensive fire pattern, where attacking troops may move through the final protective line. Once the line of fire has been pierced, the task units will charge the weapon positions. As the second wave, and other rear units, pass through the final protective line, they will likewise be prepared to engage in hand-to-hand fighting. Because heavy weapons are expected to follow closely behind the assault, they have the mission of breaking any remaining enemy resistance, as soon as the smoke clears. According to the Kwantung observers, such a large-scale use of smoke offers distinct advantages in furthering an infantry attack. Smoke, they said, is a deceptive weapon that can be employed at any time and place. It can neutralize hostile defensive fire, especially in rolling terrain, and can create in the opposing troops a sense of isolation, insecurity, and fear. The movements of the attacking troops are unrestricted and deceptive, and the speed of a break-through is increased. The use of smoke is also recommended as increasing the opportunities for hand-to-hand combat. The observers did not fail to note, however, that offensive smoke has certain disadvantages for the troops who use it. Although it may blind the enemy, smoke also blots out hostile terrain and hides the movements of defending troops. And since smoke alone will not destroy an enemy, it is only as good as the troops who use it as an aid in accomplishing a combat mission.

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