Sissi ( Finnish light infantry ) Sissi is a Finnish term for light infantry which conducts reconnaissance , sabotage and guerrilla warfare operations behind enemy lines . The word " sissi " , first attested in the modern meaning " patrolman , partisan , spy " in 1787 , comes to Finnish from Slavic and refers either to a forest bandit or his yew bow . The Finnish Army Sissi units are trained to conduct long range reconnaissance patrols , gather intelligence from concealed observation post s , raid enemy installations ( especially supply depots ) , conduct road side ambush es and pursue and destroy enemy special forces units . In wartime , the unknown number of reservists assigned to Sissi battalion s would deploy and operate as small groups up to company size . They are meant to stay behind and covertly operate against enemy forces in their area of responsibility even if regular friendly troops have been forced to retreat . Sissi battalions are part of Finnish Army local troops , unlike the jäger and armored brigade s meant for operational use . Sissi units are considered as the elites of the Army conscripts , and many of the units , such as the Paratroopers or Border Jaegers , are formed of volunteers . History . Wars between Russia and Finland have a long tradition of Finnish sissi warfare . Famous sissi leaders have included e . g . Pekka Vesainen ( abt . 1540 — 1627 ) , Tapani Löfving ( 1689 – 1777 , fought during the Greater Wrath ) , and Olli Tiainen ( 1770 – 1833 , fought during the Finnish War ) . Before the hostilities of Winter War , the Finnish Army formed 25 Independent Battalions ( Erillinen Pataljoona ) from local reservists along the border area . After the outbreak out of hostilities , a further five Sissi Battalions ( Sissipataljoona ) were formed from " auxiliary personnel " . These battalions especially those of the latter type , were below their nominal strength in both men and weaponry . These units proved to be effective in using motti tactics in their native area with light infantry weapons and skis . In the Continuation War the " ad hoc " Sissi Battalions were discontinued , but Independent Battalions were raised , 4th Independent Battalion was directly under the command of Supreme Headquarters doing LRRP and raiding missions deep inside Soviet area . In the Battle of Ilomantsi , soldiers of the 4th harassed supply lines of the Soviet artillery preventing effective fire support . In the Ladoga Karelia front the length of the front , absence roads and lack of troops prevented continuous front lines during the trench warfare period . Both armies used a chain of fortified field bases separated by the wilderness , monitoring and controlling the gaps with patrol s . Both Finns and Soviets launched raids and recon patrols into enemy territory . Battles were short clashes of lightly armed infantry groups from squadron to battalion in size , with little chance of support or reinforcements . After the Second World War , Sissi units were de - commissioned and officially Sissi training was discontinued , although many units gave Sissi training for their reconnaissance units . In beginning of 1960s , Paratrooper School was established at Utti , infantry and border guard established Sissi training companies thereafter . Term and use . In Finnish , " " sissi " " means guerrilla , but the term is somewhat misleading when referring to Finnish Defence Force Sissi troops . Sissi forces are not irregular guerrilla or militia forces ; they are part of the regular FDF - troops trained for operations behind enemy lines . Like most of the Finnish Defence Forces , Sissi battalions are composed of reservists . Their closest foreign equivalents are the Swedish Armed Forces " Jägare " troops . Sissi as a description is a person of extraordinary stamina ( or Sisu ) – e . g . " Sissi weather " ( Sissin sää ) refers to the worst possible weather conditions , for Sissi soldiers prefer these for their operations , since bad weather tends to distract enemy soldiers ( any normal soldier tends to think about getting to shelter as soon as possible when bad weather strikes ) and hide any noise caused by sissis . In the Finnish Defence Forces , Sissi is used as an umbrella term for all unconventional military applications , such as MRE s , which are called " Sissi rations " , also any improvised and / or temporary repair to any equipment is often called " sissiviritys " , literally " sissi fix " or " sissi patch " , in addition any improvised booby - trap , such as a firearm rigged to fire at doorway of a building once someone opens the door , may be called " sissijäynä " , literally " sissi prank " . Training . Volunteers with hobbies such as hunting and hiking are preferred for Sissi training , but any conscript in decent physical condition has a good chance of being assigned to a Sissi training company . Sissi troops are trained in several brigades under the Finnish Defence Forces . Finnish Border Guard , which is under the Ministry of the Interior , also trains Sissi - troops in Frontier Guard units . In the FDF , Sissi troops are trained in : In addition to this small groups of conscrips ( 8 - 10 people ) are bi - annually given marine Sissi and reconnaissance training at the amphibious brigade in Dragsvik . The group is usually taken from the " rannikkojääkärit " ( Coastal Jaeger ) infantry unit . In Finnish Border Guard sissi troops , called Frontier jaegers , are trained in each Border Guard Command . Sissi troops trained in Finnish Border guard are also taught basic duties of border guarding . In Kaakkois - Suomen Rajavartiosto special Sissi troops ( Special frontier jaegers ) are also trained in Special forces tactics and techniques . Reserve officers for all Sissi troops are trained at Reserviupseerikoulu . Rivalry between Sissi - troops in different services is traditionally high . Conscript training in these units is 6 to 12 months long . Leaders of guerrilla warfare platoons and squads serve 12 months whereas crew members serve 6 months . The medical personnel ( as also in scout units ) serve 9 months , except leaders specialising in medical training serving 12 months . Conscript in Sissi - company begins with 8 - week basic infantry training . After this training becomes more intense . Conscripts are given survival training during every season of the year , they can specialize further into reconnaissance , sniping , dog handling , battlefield medical service or signals . Sissi NCO / Officer training includes additionally signals , demolitions , extended small arms training as well as advanced escape & evasion techniques and ambush tactics . Those unable to cope for either physical or psychological reasons are either given deferments or transferred to a regular infantry training . Special Sissi NCOs are also trained to operate in Sissi platoons , called " sissiradisti " or Sissi signalists . These NCOs are trained in the use of telegraphy for long - range communications . Besides specially trained sissi troops , everyone in Finnish army at least in theory receives basic training in survival and sissi tactics . All troops and soldiers in Finnish army are theoretically capable of moving from normal warfare to sissi tactics if they are , for example , encircled or their main forces or command structure are destroyed . Sissi troops are generally not airborne , with the exception of Army Para Jaegers trained in the Utti Jaeger Regiment . Para Jaegers are trained in sissi warfare , with an emphasis on long - range reconnaissance and the addition of close - quarter battle and urban operations training . Para Jaegers carry the sissi insignia on their sleeves . Sissi troops also resemble Scout troops ( " tiedustelijat " ) , who are more specialized at gathering intelligence than the aggressive Sissi troops . In some brigades , Sissi are trained in Scout companies , and vice - versa in other brigades , as the training is quite similar . Weapons and equipment . Sissi troops are un - motorized and are not equipped with heavy weapons or equipment , their uniforms and weaponry are almost identical with regular infantry issue . Distinctive personal equipment used by Sissi are Savotta " Para Jäger " backpacks used because of extended hikes , camouflage paint and personal camouflage nets . Sissi units have fewer crew served weapons and more sniper rifles than regular infantry . Mines are an important part of the Sissi tactic of ambushing enemy convoys . They are also used to discourage pursuit after a raid and serve as defences of bivouac . Sissi training includes constructing improvised explosive device s , as well as boobytraps ( e . g . from dud artillery shells ) . Sissi units have a wide variety of land mines at their disposal , including :