| Original caption: “Inch by inch, Marine demolition crews prod the ground with their bayonets to locate Japanese landmines on the beachhead in Iwo Jima, Japan on March 2, 1945. After the taped-off area has been declared safe, supplies and equipment will be transported over this lane enroute to the front lines.” 2 5th Division Marines use an M1942 machete and a KA-BAR knife to probe for Japanese mines. A 3rd Marine stands guard with his M1 Garand rifle. The engineers wear protective flash paint. In the background, 3 M4A3 Sherman tanks of the 4th Tank Battalion and 39 millimeter (1.46-inch) guns are visible. At least 1 of the tanks has been disabled by a mine. White tape indicates the path where mines will be cleared. Mines destroyed many vehicles in the initial landings. Marines reported that Amtrac LVTs would be flung into the air by heavy mine charges. The Type 3 mine was a Japanese ceramic cased landmine used during the 2nd World War. The mine contained approximately 3 kilograms (6.6 pounds) of explosive and had a diameter of 27 centimeters (10.6 inches). A box-shaped wooden landmine using the same fuse was also produced towards the end of the war. The Japanese improvised land mine (1943) consists of a rectangular box with a cover securely fastened by friction tape. 2 holes are roughly punched in the cover through which a grenade fuse or detonator projects. The grenade fuse projects approximately 3/4 of an inch. Contained in the box are 1 Type 91 hand grenade and 12 blocks of 1/3 aluminum powder and 2/3 cyclonite (RDX). Each block is 1 1/2 inches by 3-quarter inches (3.8 centimeters by 1.9 centimeters), wrapped in waxed paper. Color is black. The grenade and blocks are firmly held in place by waxed paper. It can be used as an anti-tank mine when fused with the armed grenade. With a pull or tension detonator it can be used as an anti-personnel mine or booby trap. The anti-vehicular “yardstick” mine is an oval tube formed by 2/2 of sheet steel welded together with continuous welds and closed at both ends by steel cape held in place by single screws. 1 of the caps has a hole to take the safety wire, which is a single wire extending the length of the mine and passing through all the fuzes. The space left between the flat side of the blocks and the wall of the case accommodates the protruding heeds of the fuze and slat, allows space for the side of the case to be depressed on the fuze by the passage of a vehicle over the mine. It took 336 pounds (152 kilograms) of pressure to detonate the mine. The Type 93 (1933) mine was called the “tape measure mine” because it looked like the case of a tape measure. This pressure-sensitive mine was painted yellow or olive drab and weighed about 3 pounds. It was used for both antipersonnel and antitank purposes. The Type 96 (1936) mine was used both on land and under water. It looked like the top half of a standard spherical naval mine, weighed about 106 pounds, and had 2 projecting lead-alloy contact horns. Detonation occurred as a result of pressure applied to either horn; the pressure crushed a glass vial of electrolytic fluid contained within the horns, which triggered a chemical electric fuse. The Type 99 (1939) armor-piercing mine was referred to as the “magnetic antitank bomb” or the “magnetic armor-piercing grenade.” 4 magnets were attached to this flat, disc-shaped mine, which allowed it to be placed onto a tank or against the iron door of a pillbox. These mines were filled with Trinitrotoluene (TNT) and weighed 2 pounds, 11 ounces. They were usually coupled together for a penetrative effect of up to a 1 and quarter inches (32 millimeters) of armor plate. The Shitotsubakurai (“sudden explosion”) or lunge mine (1944), was a suicidal anti-tank weapon. It used a High-Explosive Ani-Tank (HEAT) type charge. This weapon was used by the close-quarters combat units of the Imperial Japanese Army. The weapon itself was a conical hollow charge anti-tank mine, placed inside a metallic container and attached to the end of a wooden stick. The 1st combat use was in Leyte in December 1944. The Small Type 2 (Japanese designation) or JG (United States designation) anti-boat mine was sed as an antiboat mine for the protection of beaches and reefs; also on land as an antitank mine by camouflaging. There were 5 different versions, differentiated by their welds. It had 22 pounds (10 kilograms) of Type 98 explosive, a mix of 70 percent TNT and 30 percent hexanitrodiphenylamine (HND). The Bangalore torpedo was olive drab in color and consisted of a common piece of 2-inch pipe, about 40 to 46 inches long, which was packed with TNT and cyclonite (RDX). Threaded ends on these 10-pound pipe bombs allowed for an indefinite number of them to be linked together. The Bangalore was activated by pulling a lanyard, which fired a friction primer, and was commonly used to destroy barbed wire entanglements. 1 variant was filled with 6 pounds of picric acid and was employed as an antitank mine. The 5th Marine Division Report on the Iwo Jima Operation, dated April 28, 1945, wrote: “All existing Jap[anese] roads in the regimental sector were probed for mines before being improved for our use. In order to eliminate the slow process of probing and to avoid the danger of missed mines, entirely new roads were constructed whenever possible. Four mine fields with deliberate patterns containing CAB (Conical Antitank Bomb, Type Two), HAB (Helical Antitank Bomb, Type Ninety-Six), and terracotta (Type Three) mines were found in our zone of section. The remaining hundreds of mines that were neutralized were located either in dumps or scattered indiscriminately over the terrain. About seventy-five percent of the mines were not armed. No trouble was encountered in handling Jap[anese] mines. Thousands of Jap[anese] grenades, mortar, end artillery shells were neutralized or remed from dumps in cleaning up areas. Hundreds of duds were encountered end marked or removed where safe. Few duds were blown due to the danger of inflicting casualties on our own troops.” The 4th Marine Division Report on the Iwo Jima Operation, dated May 18, 1945, wrote that “No new mines were encountered. Mines were employed, however, in much greater numbers than heretofore encountered, and while their employment still does not compare with American or European standards they were used both in fields and individually. They were judiciously placed on the beaches, on routes of advance to defensive positions, airfields and on the shoulders of roads, and wore generally covered by tire. There we evidence of considerable last-minute hasty evidence emplacement of individual mines. Types discovered included: (a) 2 horn hemispherical (Type 96); (b) 1 horn conical (Type 2); (c) 50 kilogram (110 pound) Type 97 Number 6 aerial bombs, 63 kilogram (138 pound) Number 6 Model 2 aerial bombs and 250 kilogram (551 pound) Number 25 aerial bombs buried as mines and generally activated by an attached “yardstick” mine; (d) “yardstick”; (d) terracotta (Type 3); (f) box (Type 3); (g) “tape measure” (Type 93). | |
| Image Filename | wwii1779.jpg |
| Image Size | 661.26 KB |
| Image Dimensions | 2873 x 2208 |
| Photographer | |
| Photographer Title | United States Marine Corps |
| Caption Author | Written or Adapted by Jason McDonald |
| Date Photographed | February 19, 1945 |
| Location | |
| City | |
| State or Province | Iwo Jima |
| Country | Bonins |
| Archive | Archives Branch, Marine Corps History Division |
| Record Number | Thayer Soule Collection (COLL/2266) |
| Status | Caption ©2026 MFA Productions LLC Please Do Not Duplicate or Distribute Without Permission; Image in the Public Domain |
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