Location: Karelian Isthmus Map
Constructed: 1918–1924 and 1932–1939
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Mannerheim Line is a famous line of military defences that
stretched across Karelian isthmus on the border between new
Finnish Republic and newly established Soviet Union to the
South. It was named after Russian- Finnish General Baron Carl
Gustaf Emil Mannerheim of German descent and proved more than
formidable during 1939- 1940 Winter War (30 November 1939 – 13
March 1940) when armies of Joseph Stalin almost broke their
backs trying to capture this line.
The active part of
the construction of Mannerheim Line can be divided in two
periods. The first part began right after Russian Revolution of
1917 and subsequent Russian Civil War. The first fortifications
were fairly basic. Several lines of trenches were protected by
White Russian and White Finnish troops. Their only protection
were scarcely scattered mine fields as well as barb wire. Their
effectiveness of Mannerheim Line was fairly high due to
landscape of the Karelian region. Many swamps and bogs in the
area proved to be a formidable challenge that most people never
dared to challenged. This left only few corridors for the
attack. This significantly increased effectiveness of the small
armies since their attackers were simply stuck in the numerous
bottle necks across the whole Mannerheim Line.
The
second period of Mannerheim Line construction lasted roughly
from 1932 to 1939 when the war broke out. These defenses were
significantly better. Several large concrete and steel bunkers
were constructed at the areas where the attack was most
probable. These small citadels were interconnected by numerous
trenches, underground tunnels and roads for supply and
communication. During the Winter War significantly better
equipped and larger Soviet Red Army suffered huge casualties in
their attempt to take Mannerheim Line. Eventually the war was
won by Joseph Stalin, but not after he lost 127,000 men who were
either killed or missing.
Baron Carl Gustaf Emil Mannerheim, the mastermind behind the Mannerheim Line, made an important mark in the history of the modern independent Finland. Ironically it was an unwilling contributions due to turmoil of the Russian Revolution in the early 20th century. Mannerheim comes from a German family that moved to Sweden in the 18th century and later emigrated to the Russian Empire. After finishing military academy Carl Gustaf Emil Mannerheim eventually rose to the rank of the lieutenant general in the Russian Imperial Army. During coronation of the last Russian Emperor Nicholas II in 1895 he was one of the guards during the ceremony. On the right picture above he is standing on the right side of the emperor with a white star on his chest. During the Russian Revolution Gustaf Emil Mannerheim remained loyal to the Russian Romanoff family and offered a stiff resistance against the Red Army. He even suggested that Finish White Guard (anti- Bolsheviks) should help fight the Lenin's government. This is one of the reasons why Vladimir Lenin (new leader of the newly established USSR) moved the capital of the new Soviet republic to Moscow. Unfortunately his eagerness to help the cause of the White Army went largely ignored by other Russian generals. The Russian Civil War was lost by the anti- Bolshevik coalition and Carl Gustaf Emil Mannerheim continued his service in Finland.
Construction
Design
After Finland's
independence, Soviet Russia was perceived in Finland as the only
possible military threat and Karelia as the most endangered
place of defense. Therefore, the defensive fortification of
Karelia was considered urgent. The western part was considered
the most important fortification on the Karelian isthmus,
because in the eastern part there was a water line formed by
Vuoksi, Suvanto and Taipaleenjoki, which supported the defense.
The first plan for the Karelian coast defense lines was
presented in the summer of 1918 by two Swedish officers on the
order of the Chief of the Defense Forces, Mannerheim. The plan
for the main line was close to the border and did not conform to
the waterways. The following plan was made by a German colonel.
This was very close to the line finally built. When Oscar
Enckell became Chief of General Staff in 1919, he focused on
researching and planning the fortification of the Karelian
Strait. Johan Fabritius, a fortress officer in the army of the
former Russian Empire, presented him with his own plans. In the
fall of 1919, two French officers arrived to work out the
details of the alignment.
The first phase in the 1920s
Construction of the base fortifications began in 1920 according
to Enckell's policy. He decided to favor casemates firing from
those represented in the wide firing sector as strongholds.
Their main advantage was cheapness, but Enckell's plan was
opposed because the fortification system of several intersecting
side-by-side machine guns would be stronger. Despite its
financial solution, Enckell was confronted with the view that
defense funding should rather be directed to developing the
operational capability of the Finnish Defense Forces. When he
resigned in 1924, fortification work ceased. To date, armed
fortifications had been built on the Karelian isthmus, with 62
machine-gun and 2 artillery cascades on the western isthmus and
20 machine-gun cascades and 6 artillery stations on the eastern
isthmus.
The fortification work began again in 1931 and
continued until the Winter War. At that time, the plans of the
main defense station were postponed partly southeast on the West
Strait. In the 1930s, bunkers larger than casemates were built,
two to three of which were completed each year. In the late
1930s, casemates built in the 1920s were also modernized, either
by transforming them into side-firing bunkers or by various
shelters by casting firing openings. Johan Fabritius served as
the head of the Fortress Office from 1935 to 1938. At the start
of the war, there were 42 machine-gun bunkers at the start of
the war, 25 of which were more modern on the West isthmus and 17
older on the East isthmus. The eastern isthmus also had the old
6 artillery stations. The Mannerheim line used 14,520 cubic
meters of concrete, while the shorter VT line used about 400,000
cubic meters.
The second phase in the 1930s
Field
equipment work began in the late 1930s. Much of the field
equipment was built in the summer of 1939 as volunteer work and
during YH. A total of 606 machine gun colonies and ditches were
built at the main station (438 for the western isthmus and 168
for the eastern isthmus). 331 km of barbed wire barriers were
towed (214 km for the western isthmus and 117 km for the eastern
isthmus) and 136 km of boulders used as armored barriers were
reduced by 136 kilometers (85 km for the western isthmus and 51
km for the eastern isthmus). As the main station was about 140
kilometers long, it received an average of 4 field-fortified
machine gun colonies, 2.5 kilometers of barbed wire barriers,
and 1 kilometer of armored barriers per kilometer.
Of the
length of the main station, 80 kilometers rested on the water
body and the land front was about 60 kilometers. The terrain of
the line was relatively shallow throughout. Of the soil in front
of the land front, 30 per cent was swamp and 70 per cent hard
land. About 75 percent of the hard land was forest land and
about 20 percent cultivated. The aim was to place a support line
0.5–1 km behind the main station line.
Only the main
station had structural strength. The intermediate station and
the rear station were mainly field fortified and partly at the
design stage.
Structure by blocks
Blocks of the main
station during the Winter War
Blocks from the main station of the Mannerheim
line from west to east during the Winter War:
There were two
coastal artillery forts on the coast of the Gulf of Finland that
supported the main station. Saarenpää Fortress was located at the
south-southwestern end of Koivistonsaari. Its main weapons were six
254-millimeter and two 152-millimeter cannons. The coastal fortress
of Humaljoki was located on the shores of the Karelian coast next to
Koivistonsaari. Its main weapons were six 152-millimeter cannons.
The task of the forts was to prevent the Soviet navy from entering
the Vyborg Bay.
The Inkilä block was a 9-kilometer long line
from Kyrönniemen Bay in the Gulf of Finland to the southern tip of
Lake Kuolemanjärvi. The Red Army used three names for the Inkilä
block: the Suurpentikkälä node, the Inkilä node and the Muurila
node. There were seven bunkers in Inkilä. Inkilä received
significant fire support from the coastal cannons of the Gulf of
Finland.
The Summankylä block was a 4-kilometer-long line
from the northernmost bend of the Summajoki River to Summajärvi. The
sum village had four casemates and 13 bunkers.
The Summajärvi
block was a 2-kilometer-long line between Summajärvi and Munasuo.
The Finns have also called it the Lähte block and the Munasuo block,
and the Soviets have called it the Intercontinental Resistance Zone.
Summajärvi had three bunkers and six casemates.
The Leipäsuo
block was an 800-meter-wide strip between the St. Petersburg and
Vyborg line and Tassiolampi. The Red Army called the Leipäsuo block
a Railway Node. The bread barn had two bunkers with five casemates
behind it.
The Suurniemi block was a line about 2 km long
from the southwestern shore of Lake Muolaanjärvi to the southwest of
Suurniemi. The Red Army called the block Väisänen's resistance node.
The block had five armed bunkers.
The lake stock line was
more than 30 kilometers long from Muolaanjärvi to Vuoksi's
Pasurinlahti, which ran across Yskjärvi, Kirkkojärvi and
Punnusjärvi. The line was only field fortified. For example, there
were 167 machine gun ditches.
The northern shores of Vuoksi
and Suvanto formed a line of defense. The main crossing points of
the lakes had a total of six barracks, consisting of artillery
stations and machine gun stations.
The Taipale block was a
line from Suvanto to Mustaoja and the bend of the Taipaleenjoki and
Kaarnajoki rivers. There were eight machine gun missions in the
block.
The coastal artillery of Ladoga consisted of the
Järisevä coastal fortress and the Kaarnajoki radiator. Järisevä was
located in Järisevänniemi, north of the Taipaleenjoki River. There
was one 120-millimeter and two 87-millimeter cannons. The Kaarnajoki
radiator was located inland, kilometers from the Kaarnajoki River,
northeast of Koveroja. There were four 152-millimeter cannons. The
coastal artillery of Ladoga provided significant fire support to the
block of Taipale.
The fortified blocks of the intermediate
station during the Winter War
At the end of November 1939, the
main station was moved further south so that the base fortifications
between Muolaanjärvi and Äyräpäänjärvi, which had previously
belonged to the main station, were marked as part of the
intermediate station and the lake base line was established as part
of the main station.
The lane of the Muolaan isthmus was
about three kilometers wide between Muolaanjärvi and Äyräpäänjärvi.
There were 12 old casemates and 12 bunkers completed by February
1940.
The Salmenkaida lane was about 9 kilometers long on the
northern shore of the Salmenkaitajoki between Äyräpäänjärvi and
Vuoksi. The Red Army called it the Ritasaari Resistance Node. There
were eight old casemates and a bunker completed by February 24,
1940.
The battles of the Winter War
The Karelian army was
responsible for the defense of Karelia. The focus was on the Western
Strait, which was defended by the Second Army Division with four
divisions. The East Strait had the 3rd Army Corps with two
divisions. At the beginning of the Winter War, protection forces had
been concentrated on the Karelian coast, the task of which was to
delay the attacker until the field army could be stationed in the
main station. The main station was then tasked with repelling all
attacks.
Fighting in the main station
The first offensive
of the Red Army
The task of the 7th Soviet Army was to break the
positions of the Finns, conquer Vyborg and proceed to the level of
Helsinki and Päijänne. According to the Red Army, the best route of
attack on the Karelian coast was a narrow lane from Valkeasaari to
Vyborg according to the St. Petersburg-Vyborg line.
The Winter War began on November 30, 1939, and the
Finnish Defense Forces withdrew to the main station by December 10.
On the western isthmus, Soviet 7th Army troops reached a central
position south of Lake Muolaanjärvi on December 12 and began their
first burglary attempt on December 17. An attempt to cross the
Taipaleenjoki River began on the eastern isthmus on 6 December. The
Red Army infantry attacked the forts with the support of artillery
and the Air Force. The bunkers withstood cannon fire well and the
bombings were inaccurate. One radiator fired 1,800 grenades per
bunker, only succeeding in removing small pieces from it. The
attacker's progress remained modest and the losses large. The 7th
Army suspended the offensive on 26 December.
Another
offensive of the Red Army
On January 7, 1940, the Red Army formed
the Northwestern Front to take on the task of advancing in the
direction of Vyborg. The front consisted of the 13th Army, which was
tasked with breaking the Mannerheim Line on the East Strait, and the
7th Army, which was now focused only on the West Strait.
On
February 1, the Northwest Front launched a major offensive that
focused on the Western isthmus in the blocks of Summankylä and
Summajärvi. The main station began to break in Summa on February 11,
when the Red Army managed to siege and detonate several base
fortifications.
The Commander-in-Chief of the Finns gave
permission to leave the main station on 15 February. The next night,
a retreat was started from the east side of the breakthrough site
from the main station between Lake Muolaanjärvi and Vuoksi to the
transferred intermediate station at the level of Lake Äyräpäänjärvi.
Withdrawal from the Inkilä block began on 16 February without combat
contact to avoid blockade. The Humaljoki Fortress was withdrawn on
19 February and the Saarenpää Fortress on 23 February.
On the
eastern isthmus, all casemates in the Taipale block were destroyed
or lost to the Red Army in January 1940 at the latest. One of
Suvanto's fortifications was abandoned shortly before the end of the
war. On March 11, the Finns began to detach artillery and crew from
the main station to the rear lines of defense. On the eastern
isthmus, however, the main station lasted until the end of the war.
Fighting in the midfield
On the western isthmus, the
intermediate position proved to be weaker than the main position
because its base fortifications were less frequent and outdated, and
the terrain was less favorable to the defender. The midfield defense
lasted nine days.
The Finns began to withdraw from the
intermediate position of the Western Isthmus to the rear position on
February 27 at the behest of the Isthmus Army. At that time, most of
the base fortifications of the Muolaan isthmus strip and the
Salmenkaida strip were Destroyed.
Fighting in the background
When the defenders moved to the rear position on the West Strait, it
was poorly equipped and its field fortifications unfinished. In
Vyborg Bay, the rear station was concretely unsafe.
In the
battle of Vyborg Bay, the Red Army reached the rear position on
March 1, when its patrols tried to invade Teikarsaari. The Red Army
passed the rear station in the Vyborg Bay on March 3, when the Finns
withdrew from Teikarsaari less than a day after the battle. The weak
rear position delayed the attacker's progress across the Gulf of
Vyborg to the mainland by only a week, when the Finns gave up the
rear position in the Vyborg Bay by March 10 at the latest. Inland,
the Red Army rose for the first time in Häränpähtiemi on March 2 and
received its first permanent bridge headquarters in Vilaniemi on
March 5.
In front of Vyborg, the Red Army reached the rear
position on March 1. Here, the rear station began to break on March
3, when the defender finally lost the nearby islands that belonged
to the rear station and a counterattack on land to recapture the
lost stations failed.
On the central isthmus, the front line
reached the rear position on March 11th.
Mannerheim line
after the Winter War
The Soviet Union destroyed the concrete
defense equipment when it took possession of Karelia after the end
of the war. In the Continuation War, the line was irrelevant, only
the northern parts of the line, which belonged to the VT and VKT
lines, were rehabilitated in 1943–1944.
The 79-minute
documentary Linija Mannergeima, directed by Vasily Belyaev, was
premiered in the Soviet Union on April 10, 1940. The filmmakers
received Stalin’s 2nd Class Award.