The SMi-35 mine, S-mine, or "Bouncing Betty" was an anti-personnel, bounding mine used by Germany during World War II.


S-Mine stood for Schrapnellmine which meant shrapnel mine in German. It could either be activated by a trip wire or by a pressure sensor at the top of the rod holding the three prongs. One of the notable features of the Bouncing Betty is that once activated, a black powder charge sends it flying up into the air until it reaches about waist height (2 feet, 0.6 meters), then it explodes sending all of the 350 steel balls placed inside of it flying everywhere covering a blast radius of about 149.9 meters maximum, though the effective blast radius was 20 meters[1] The time it took for the mine to detonate the main charge was about 4 seconds.

This had a fairly big psychological effect on allied troops who encountered it. The average weight of the S-mine was about 4 kg and the height was 13 centimeters. About 190 grams of the weight was for the explosive TNT charge and the rest was internal and external components such as the steel tin protecting the mine.[2] To protect German troops who were setting up the mine, a safety pin was located near the pressure sensor and once this safety pin was removed the mine was armed. A trip wire would do almost the same thing because the person pulling the wire would pull out the pin arming the system which in turn would detonate the mine.

When planting the mine, German troops left the three prongs just above the surface so they would stay virtually invisible. Allied soldiers took advantage of the safety pin when disarming the mine by putting a new pin in the safety pin socket which disarmed the mine. the only variant of the SMi-35 was the SMi-44 which came into use in 1944-1945.


The SMi-44 was introduced because of the need for an effective yet cheaper to make mine as the SMi-35 was fairly expensive to make. The SMi-44 was not only cheaper to make, it had some different mechanisms and other small changes, but in reality they were very similar to each other.


The S-Mine was developed in 1935 and first used against French forces during the Fall of France. S-Mines were also used in North Africa and Normandy. Finalnd also used the S-Mine during the Continuation War with little success. The effectiveness of the S-Mine proved incredible and that is why many mines from the United States, France, and the Soviet Union were based on it. There are some myths about the S-Mine like the one that says if you don't take your foot off of the mine, it won't detonate. These are false as even if you don't take your foot off of the mine, it will still detonate and perhaps knock the person off the mine killing him/her when the mine's main charge is activated.


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