Editing Mannerheim Line (section)

==Debate on the strength of the Mannerheim Line==
The first month of the Finnish campaign was humiliating for the Red Army. By the third week of the war, Soviet propaganda was working hard to explain the failure of the Red Army to the populace, and claimed that the Mannerheim Line was stronger than the [[Maginot Line]].<ref name="Trotter15">[[#Trotter2002|Trotter 2002]], pages 203–209</ref> The Finns originally aimed to make its defence line impregnable, however actual construction progress came nowhere close to this goal by the time the Winter War broke out{{citation needed|date=October 2023}}, in contrast to the Maginot Line which effectively deterred a cross-border assault. The Finns had funds and resources for only 101 concrete bunkers; the equivalent length of the Maginot Line had 5,800 of these structures which were also linked by underground railway connections.<ref name="ManninenStalininkiusa5">[[#ManninenStalininkiusa2002|Manninen 2002]], p. 57</ref> The weakness of the line is illustrated by the fact that the amount of concrete used in the whole Mannerheim Line—{{convert|14,520|m3|ft3|disp=or|abbr=off}}—is slightly less than the amount used in the [[Helsinki]] [[Helsinki Opera House|Opera House]] ({{convert|15,500|m3|ft3|disp=or|abbr=off}}).{{citation needed|date=October 2023}} The much shorter [[VT-line]] used almost {{convert|400,000|m3|ft3|sp=us}} of [[concrete]].

However, "flexible" defense lines (Mannerheim Line, [[Árpád Line]], [[Bar Lev Line]]) were not based on dense lines of [[concrete]] [[bunker]]s and [[Pillbox (military)|pillboxes]] (as the [[Maginot Line|Maginot]] system was). The main intention of flexible type [[Trench warfare|field fortification]] was to close potential traffic and attack barriers with multiplied [[Anti-tank trench|anti-tank ditches]], [[Czech hedgehog|hedgehogs]], and [[Dragon's teeth (fortification)|dragon's teeth]]. These were followed by a complex system of [[Trench warfare|ditches and barbed wire obstacles]], which protected the anti-tank barrier against sappers, bridge-layer tanks, and engineer teams. Therefore, the enemy was forced to attack trenches as in World War I, at the cost of numerous losses, without armor and direct fire support. It was termed "flexible defense" because defending soldiers were not 'locked' into bunkers, but the defensive platoons could be regrouped between field fortifications ([[Field fortifications|wood-earth firing posts, dugouts and pillboxes]]). They would also have the option of carrying out a [[counterattack]]. All soldiers and weapons had multiple firing positions in order to make it difficult to keep them under fire. Concrete bunkers were usually only shelters; just a few had crenels. Concrete pillboxes were side-firing in order to defend [[anti-tank obstacles]].<ref name=":0"/>

Maginot and [[Siegfried Line|Siegfried]]-like bunkers had numerous weaknesses, such as having destructible air inlets and firing holes, being too large ([[camouflage]] and costs), and yet being vulnerable to small [[Sapper|sapper teams]] (at [[Sedan, Ardennes|Sedan]], a few German soldiers destroyed several machine-gun bunkers with pre-fabricated bombs and smoke grenades), and being blinded by small concentrated smoke screens. The flexible defense lines were almost immune to small sapper teams or small smoke screens, and had no easily targetable objects.<ref name=":0" />