German S-mine (Schrapnellmine in
German), also known as the
"Bouncing Betty", is the best-known version of a
class of mines known as bounding
When triggered, these mines launch into the air
and then detonate
at about waist height.
The explosion projects a lethal shower of steel balls and steel
fragments in all directions. The S-mine was an anti-personnel landmine
developed by Germany in the 1930s and
used extensively by German forces during World War II
. It was designed to be used in
open areas to attack unshielded infantry. Two versions were
produced, designated by the year of their first production: the
SMi-35 and SMi-44. There are only minor differences between the two
The S-mine entered production in 1935 and served as a key part of
the defensive strategy of the Third
. Until production ceased with the defeat of Germany in
1945, Germany produced over 1.93 million S-mines. These mines were
responsible for inflicting heavy casualties and slowing, or even
repelling, drives into German-held territory throughout the war.
The design was lethal, successful and much imitated and remains one
of the definitive weapons of World War II.
Allied forces to encounter
the S-mine were French soldiers who were
attempting minor probes into the coal-rich German Saar region in
September 7–11, 1939, during what is known as the Phony War.
The S-mine contributed to the
withdrawal of these French incursions. The mine's performance in
the Saar region affirmed its effectiveness in the eyes of the
German leadership and prompted the United States and other
countries to attempt to copy the design. After their experience,
the French nicknamed the mine "the silent soldier".
Germany used the S-mine heavily during the defense of its occupied
territories and the German homeland during the Allied invasions of
and North Africa
. The mines were produced
in large numbers and planted liberally by defending German units.
example, the German Tenth Army deployed over 23,000 of them as part
of their defense preparation during the Allied invasion of Italy.
S-mines were deployed on the beaches of Normandy
in preparation for the D-Day invasion, as
part of a general program of heavy mining and fortification. The
mines were subsequently used to defend German positions during the
Battle of Normandy
and in the
defense of Northern France and the German border. S-mines were
typically used in combination with antitank mines to resist the
advances of both armor
It was during the Allied actions in Europe that the S-mine gained
its cynical nickname "Bouncing Betty" from American infantrymen.
The S-mine had a great psychological effect on Allied forces
because of its tendency to seriously maim infantrymen's limbs or
rather than killing them. In his
book Mine Warfare on Land
, Lt. Col. Sloan described the
S-mine as "probably the most feared device encountered by Allied
troops in the war." Exact death tolls inflicted by the S-mine are
not known, since the Allies did not record whether a death was
caused by a particular type of weapon, only whether or not the
death occurred in the course of battle. Civilian casualties are
even more a matter of speculation.
S-mine production ceased after the end of World War II. No
information has been discovered as to the exact fate of the
remaining stockpiles of the mine, but it can be assumed a majority
were destroyed as part of the disarmament of Germany after their
surrender. It is likely some were preserved for study and reverse engineering
by the conquering
Allies. Many direct imitations of the S-mine appeared in the years
following World War II.
During the military occupation of Germany and the postwar
rebuilding of Europe, the American Army Corps of Engineers
, the newly
established French government, and the British Ministry of Defence
engaged in one of the most prolonged and successful mine-clearing
operations throughout Western Europe. France deployed a variety of
personnel to undertake this task, including 49,000 German prisoners
of war. This joint operation eliminated a majority of the remaining
fields of landmines on the war-torn western half of the continent
and was greatly assisted by the German policy of clearly marking
and accurately recording the locations of minefields.
However, incidents involving accidental explosions of landmines in
North Africa, the former Warsaw Pact
countries, France, and Germany still occur sporadically. North
Africa and Eastern Europe have a particularly large amount of
uncleared World War II-era minefields, lost in the desert sands or
forgotten by authorities. In Libya, for example, the Red Cross
estimates over 27% of farmland is unusable due to World War II
minefields. While German documentation says the S-mine had an
effective lifespan of two to seven years once planted, the
explosive charge could still operate in mines to this day.
S-mine in a museum
The German S-mine was a steel
than tall without its sensor and only in diameter. A steel rod
protruding from the mine's top held the main fuse
, where its trigger or sensor was
attached. The SMi-35 had a central fuse, while the SMi-44 had an
offset fuze. It weighed approximately , with the weight depending
on whether it was loaded with the lighter powdered or the heavier
The main charge of the mine used TNT as its explosive; the
propelling charge was black powder
standard pressure sensor used a percussion cap
to ignite it.
The main fuze was designed to delay the firing of the propelling
charge for approximately four seconds after the mine was triggered.
The explosion of the propelling charge sent the mine upwards into
the air and activated three short-delay pellets between the
propellant charge and the three detonators. These short-delay
pellets delayed the mine's detonation long enough for it to reach
an appropriate height before exploding.
The standard pressure sensor was designed to activate if depressed
by a weight of roughly or greater. This was to ensure it was not
detonated by wildlife or natural impacts. The tripwire adapter for
the mine was a shallow Y-shaped device and would trigger the mine
if the tripwire was pulled away from the mine.
Diagram of S-mine detonation
The S-mine was normally triggered by a three-pronged pressure fuze.
It could also be modified to be triggered by a tripwire
. A special tripwire adapter was provided
by the German army. The steel tube that held the fuze
was threaded to accept any standard German igniter
or trigger, allowing the sensor to be removed and the mine to be
deliberately triggered by a human operator. When triggered, the
mine functioned in two stages (see diagram).
- First, the mine was fired up into the air by a small propellant
- Approximately a half-second later, the main charge detonated at the optimum height to kill or severely
injure anyone in the immediate area.
- The main charge of the mine was surrounded by roughly 360 steel
balls, short steel rods, or scrap metal pieces. These became metal
shrapnel that sprayed
horizontally from the mine at high velocity.
The time between triggering and ignition of the propelling charge
varied between 3.9 and 4.5 seconds, depending on the age and
condition of the mine. According to German documentation, the
S-mine was lethal within and could inflict casualties
within . American training
manuals warned of casualties at up to about . A common
misconception about the S-mine is that it would not detonate until
its victim stepped off the trigger. This fallacy was propagated by
incorrect United States propaganda
World War II. The mine would detonate whether the trigger was
released or not. Standing still or attempting to run from the
S-mine would be equally dangerous. The most effective way to
survive the mine's detonation would not be to flee but to fall to
the ground lying face down as quickly as possible. Even then,
injuries were likely.
S-mine dischargers, in the form of angled tubes attached via
brackets to the hull, were also used for anti-infantry defence by
Wehrmacht armoured vehicles. Early versions of the Tiger I
were equipped with five such devices.
Detection and disarming
An American infantryman probes for
landmines using a knife.
The S-mine was constructed mostly of metal, so it could be easily
detected by metal detectors
such expensive and bulky equipment was rarely available to infantry
units and was prone to malfunction. The mine could also be detected
through careful manual probing, a time-consuming process. Using a
knife or a bayonet, an infantryman would probe at a low angle
through the soil. It was important to probe at an angle that would
not accidentally depress the pressure sensor.
Once an S-mine was discovered, disarming it was fairly simple. To
prevent triggering while the mine was being planted, the German
pressure sensor featured a hole where a safety pin kept the sensor
from being depressed. This pin was removed once the mine was
planted. If the discovered mine was fitted with the pressure
sensor, the disarming personnel would slip a pin (such as a sewing
pin) into this hole. If the device was armed with a tripwire or
electrical trigger, this could simply be cut. Germans were known to
use booby traps
to discourage this, so
caution was suggested. The mine could then be removed carefully
from the ground and the sensor easily unscrewed. If it was deemed
necessary to render the mine completely inert, three plugs on the
top granted access to the three detonators inside the mine. These
could be unscrewed and the detonators removed.
The following diagrams show the SMi-35 landmine's internal
mechanism, together with the three-pronged pressure fuze. The
safety pin for the fuze and the three removable plugs for the
detonators are clearly visible. These diagrams were issued as part
of a US Army field manual on landmines in 1943.
The S-mine was an extremely successful design. Bounding mines based
on its design were introduced by other countries.
Finnish army began purchasing the SMi-35 model S-mine from
Germany following the Winter War.
This was part of a larger military assistance agreement between the
two nations. Finnish forces achieved great success with the S-mine,
but the monetary cost of the mine was considerable. During the
, the Finns
attempted to produce their own version of the mine but with no
success. The Finnish nickname for the mine was
French Mle 1939 mine was
inspired by the success of the S-mine.
In 1940, Major Pierre
Delalande of the French Corps of Engineers managed to escape the
German conquest of his country and reached the United States with
the Mle-1939 plans. These plans led to the development of the
American M2 mine, which was fielded in 1942 but proved
deficient in combat. The American army was impressed by the
S-mine's role in thwarting the French offensive in
the German Saar region at
the beginning of World War II and continued further work on
After the war, the American army developed
their M16 mine
directly from captured
Union also based the design of its OZM
series of landmines on the German S-mine.
tended to be far simpler internally; instead of being filled with
steel balls or scrap metal, the OZM-4 mine was given a solid
cast-iron body that would fragment on its own. Later, the OZM-72
bounding mine was filled with steel rods, returning to the original
concept of the S-mine. Both of these mines are still being produced
nations that have produced S-mine-inspired designs include the
Republic of China and Italy.
use of landmines remains a controversial issue to this day.
Antipersonnel mines like the S-mine have been the subject of
repeated treaties and human-rights objections and are the subject
of extensive international debate.
- US War Department Technical Manual TM-E 30-451: Handbook on
German Military Forces, 1945. (Ch. VIII, Sec. V.5.a-b). (available online)
- JTV. Finnish Army 1918–1945, last updated 12 March
- Lieutenant-Colonel C.E.E. Sloan, Mine Warfare on Land,
Brassey’s, London, 1986.
- Lieutenant-Colonel John Ingraham & Col. Dalton Jones.
Technical Intelligence Bulletins 8(5), 2003. (available
- *Klaus H. Huebner, Long Walk Through War: A Combat Doctor's
Diary, Texas A&M University, College Station, 1987.
- US Army Field Manual FM 5-31, 1943.