In the forest battles north of Lake Ladoga, the Finns beat the Russians by adopting a style of warfare different only in detail from the tactics that caused Braddock’s defeat in colonial America two centuries earlier. The invader was outmaneuvered and outfought by men defending their homeland, fighting in the style that was best suited to their native terrain—guerrilla tactics on a massive scale—and compensating for their numerical and technological inferiority with speed, daring, and economy of force. The image of the outnumbered but intrepid ski warrior that emerged from those victories became, in the minds of newspaper readers the world over, the most vivid and inspiring symbol of Finnish resistance. There wasn’t room in most people’s minds for any other.
But in some ways, the struggle for the Karelian Isthmus proved the Finns’ mettle even more than their sensational triumphs in the northern wilderness. The Isthmus gave little chance to exercise those guerrilla tactics; the restricted nature of the terrain created a classic and thoroughly conventional military situation: a heavily fortified line, its flanks protected by large bodies of water (at least until that water turned to ice), manned by stubborn defenders, being assaulted by a powerful and numerically superior attacker. The Finns would win or lose on the basis of their conventional, professional, military skills, the fiber of their discipline, the worthiness of their commanders—and above all else, on the depth and stubbornness of their sisu. That bristling little word was once the most famous Finnish idiom ever to become part of the outside world’s vocabulary. It can be translated as “guts” or “spunk” or “grit” or “balls,” or as a combination of all those words together. The word in Finnish has nuances that resist easy translation.
Largely to excuse the enormous losses they incurred during their frontal assaults against it, the Russians went to much trouble during the latter weeks of the war, and in all their published accounts of it since, to inflate the Mannerheim Line’s reputation to fantastic proportions. The usual claim was that it was “as strong as” or “stronger than” the Maginot Line. After the armistice, their propaganda trumpeted that the breaching of the Mannerheim Line was “a feat without parallel in the annals of war.” Naturally, while the fighting was going on, the Finns did nothing to discourage the enemy’s propaganda efforts on their behalf.
Since the war, however, Finnish historians have belittled the line’s strength perhaps too much, insisting that it was mostly just conventional trenches and log-covered dugouts and that the real strength of the Mannerheim Line was the sisu of the troops manning it.
The truth lies somewhere in between. It is still possible to get a firsthand impression of the strength of the line’s fortifications by examining the ruins of several of its blockhouses. These can be found within 100 meters of the main road between Viipuri and Leningrad, on the site of what used to be Summa village—that is to say, at the most critical and vulnerable point of the entire Finnish defense. The biggest and most elaborate bunkers, with the exception of the coast-defense forts on the gulf shore and on the coast of Ladoga, were located north of Summa, covering the Lähde road. These probably still exist, but they are far from any road that tourists normally travel, and the entire Isthmus is still considered a militarily sensitive area by the Russians. One would be well advised not to go wandering through the woods.
The surviving bunkers show signs of terrible damage—the author crawled around inside one that looked as though it had been beaten into the earth with a giant ball-peen hammer—but enough was left to draw some conclusions. First of all, these were not anything as big or elaborate as the multi-layered dinosaurs of the Maginot Line. They were, however, massive, thick, multi-chambered blockhouses; if manned by stubborn defenders, they would have been very tough to take and even harder to knock out with fire alone.
Just how strong was the line, then? Here, the researcher runs into considerable confusion. Every general who published a book about the Winter War gives a different estimate of the line’s strength. Mannerheim, in his Memoirs, states that the entire line contained only sixty-six “strong points,” of which about forty were too old or thin to withstand much modern artillery fire.
General Öhquist, distinguished commander of the Finnish Second Corps, which bore the brunt of the Isthmus fighting, offered a different breakdown of figures. From the Gulf of Finland to the Vuoksi Waterway, the line had ninety-three “strong points,” of which Öhquist judged forty-nine to be of inferior quality and durability; along the Vuoksi Waterway, north to Lake Ladoga, Öhquist counted some twenty-six “strong points,” all of them old, but many of them modernized in the months before the war.
Perhaps it depends on how one defines the term “strong point.” Mannerheim was apparently listing only those positions that were “strong” by the standards of 1939—bunkers made of reinforced concrete. Öhquist’s figures seem to include a number of the stronger field fortifications—log-roofed bunkers or elaborate earthworks. The Russians, for their part, added to the confusion by the flat claim that they captured more than “300 forts,” whatever that may mean; the total is exaggerated even if it includes the coastal defense works in the Koivisto sector, on the gulf islands, and those in the secondary defense line manned by the Finns after the Mannerheim Line was breached in February.
Finally, in the early 1960s, a Finnish historian tried to settle the matter once and for all by the simple method of counting the strong points listed on contemporary maps. He came up with a total of 109 reinforced concrete positions for the entire eighty-mile length of the line.
The line was strongest on its flanks, where fixed coastal defenses mounted cannon whose calibers ranged from 120 mm. to 254 mm. Even in midwinter the ice on that part of Lake Ladoga is too treacherous to bear the weight of heavy equipment; too many underground streams feed into the lake from the Finnish shore. Nor is the much thicker gulf ice usable until February, after several weeks of hard freeze. The line could not, therefore, be turned by an outflanking maneuver, at least not in the first weeks of fighting.
The most dangerous sector of the line was astride the shortest route between Viipuri and Leningrad, where two major roads went through the village of Summa and toward the village of Lähde. This ten-mile stretch, between the Summajoki River and Lake Muolaanjärvi, also ran through some of the poorest defensive ground on the Isthmus—rolling, stumpy, comparatively open farmland—and the ground was quite hard by December. Good tank country.
To plug this gap, the so-called “Viipuri Gateway,” the Finns had constructed thirty-five reinforced concrete positions, including some of the biggest and most elaborate they had ever built. Only about fifteen of them, however, a ratio of about one per kilometer, were of modern construction.
The approaches to the line were heavily fortified. Vast fields of barbed wire entanglements had been erected, and thousands of mines had been seeded on all likely avenues of approach. The entire Karelian Isthmus was belted as well by a line of antitank obstacles, five to seven rows deep: granite monoliths that had been sunk into the earth, at the cost of much sweat, during the final summer of peace. It came as a very nasty shock to the Finns to discover that most of these rocks were too short to actually stop Soviet armor; the Russians knew what they were doing when they adopted the Christie suspension design, for it made their vehicles agile and gave them good climbing traction. Still, the rocks did help; if a tank hit one at the wrong angle, it would throw a tread and just hang there, a veritable sitting duck. Also, when climbing over the rocks, the tanks’ lightly protected underbellies would be exposed, and a lucky grenade toss, or even a burst of heavy machine-gun fire, could do damage.
All things considered, then, the Mannerheim Line was no pushover. Manned by stubborn troops, it was a formidable defense line, even if it fell far short of André Maginot’s monument to militarism’s Age of High Baroque. But it had glaring weaknesses: the pillboxes were sited too far apart to give mutual fire protection to one another. As soon as the Finnish infantry on either side had been killed or driven out, there was nothing to prevent Red infantry from swarming over isolated strong points, or Russian tanks from simply driving up and parking in front of the firing ports, a tactic that would prove devastatingly effective in many battles. Most of the modern bunkers had firing chambers large enough to accommodate a Bofors antitank gun, but there were too few of these precious weapons to go around and none to tie down in static defensive roles. Most of the bunkers, therefore, were armed with nothing heavier than Maxim guns.
Perhaps even more critical was the lack of Finnish artillery to back up the line; heavy guns were so few, and ammunition so limited, that many Russian attacks that could easily have been broken up by shell fire were allowed to proceed without interference. When Red infantry swarmed over the pillboxes, the men inside could not call down shrapnel barrages to clean them off. And, in the final days of the struggle for the line, when the Russians wheeled up dozens of flat-trajectory field guns, in plain sight, and fired massed salvos at the bunkers’ firing slits, there was nothing heavier than mortars to fire back at them with.
Naturally, when the Russians started inflating the line’s reputation to fabulous proportions, it was not in Finland’s best interests to issue disclaimers. The problem was that the Finnish public, too, believed that the line was impregnable. Old soldier that he was, Mannerheim knew there was no such thing as a truly “impregnable” defense. He flatly predicted, even before the first battles were fought, that the line that bore his name could be shattered whenever the enemy decided he was willing to absorb the enormous losses it would require.
Before the war there had been heated debates among the Finnish generals about the final configuration of the line. Mannerheim and many of his staff believed the defenses should be placed so as to incorporate all of the older fortifications. A different theory was propounded by General Öhquist, who believed that if some of the more exposed older positions were abandoned, the other strong points could be improved by earthworks in such a way as to increase the overall depth of the defenses. Had his suggestions been followed, the Russians would at least have been denied certain advantages of cover and observation that they later enjoyed. Over Öhquist’s objections, however, the final configuration of the line was drawn so that the defenses bent inward to form a sort of elbow near the village of Summa. This salient would be the greatest danger zone on the entire Isthmus because a Russian penetration there, or at any point for ten kilometers north or south of Summa, would open up the rear of the entire Mannerheim Line. Ideally the line should have been laid out so that Summa formed a reserve position, a backstop. As finally conceived by the high command, the line would have been satisfactory only if Finland had possessed sufficient trained reserves to launch big counterattacks against the Russians drawn up before it; and Finland did not.
After the war, Marshal Timoshenko, who masterminded the cracking of the line, showed Nikita Khrushchev proof that Soviet intelligence had all along been in possession of detailed maps of the Mannerheim Line; but nobody had bothered to consult the intelligence service before starting the war. “If we had only deployed our forces against the Finns in the way even a child could have figured out from looking at a map, things would have turned out differently.”1
1Crankshaw, ed., 301.