Polka Saves Lives

The time-line of WWII is very complicated and there were some conflicts within the war that began beforehand, and others which only continued unabated into further conflict afterward. In the U.S. the war is often taught inaccurately as ending abruptly in the European theater in April of 1945, and in the Pacific theater with the dropping of a nuclear bomb on Hiroshima in August of 1945. Perhaps it's Hollywood which gives America such a love of tidy endings which wrap up all the plot lines. Real  history is a continuum without end. Every event begets another ad infinitum.

After the Winter war, the Soviet invasion of Finland (Nov. 1939 - mar. 1940) Finland and Nazi Germany invaded the USSR. This is called Continuation War. The Finland was trying (mostly) to regain lost territory, while Germany... I'm sure you've heard. It was a very active conflict causing about 85,000 deaths. The Continuation War ended in September of 1944, with the Moscow Armistice. There is a lot to unpack there. So let's skip ahead to the interesting bit of radio trivia.
We start in the city of Finnish Viipuri which today is on the other side of the border in the Lenningrad Oblast as Vyborg, Russia. The Finish army defeated the Russians and on August 31st, 1941 they had a victory parade. Shortly thereafter they discovered the landmines.  The retreating Soviets planted radio-controlled land mines throughout the city of Viipuri. These events are covered with a bit of detail in the book Finland at War by Vesa Nenye and Peter Munter.

Accounts indicate that these mines were designed to be triggered by an a triad— a three-note chord. I think this is somewhat inaccurate. The trigger was probably an AM radio wave carrying a triad tones. All account indicate the remote control originated in Leningrad (now Saint Petersburg). This is 85 miles away. More likely the concern was that they would be triggered during the retreat to Leningrad. Nonetheless the signal was in all likelihood a single AM frequency, bearing the triad detonate signal.  Were it not, jamming would be infinitely more complicated. You can also find more information on this in the book Finland at War by Vesa Nenye and Peter Munter.

The book Wireless Communications Security by Jyrki T. J. Penttinen also described the mechanism. I paraphrase for clarity:  A three-note chord was played on the frequency the radio was tuned to, causing three tuning forks to vibrate. Once the Army and Yleisradio experts discovered how the mines worked, a Yleisradio mobile transmitter was brought to Viipuri, and Vesterinen's recording of the polka was played on the same frequencies the mines used. The song was played continuously for about 1,500 repetitions in the beginning of September 1941, after which alternative equipment was used to continue the radio jamming operation until February 2nd, 1942.  The word Yleisradio just means "General Radio" or "General Broadcast". In this context I read it to mean "radio engineers", or "radio operators". Today it's also the name for Finland's Public Radio entity, like the BBC, CBC or NPR.

But there are slightly different versions of these events. The victory parade may be a later revision to the tale. But the victory it self was real. It was the 3rd time in 4 years the Finns had taken Viipuri back from the Russians, there probably were multiple parades over those years. A U.S. Department of Defense document described it thusly:

"Although the Russians retreated in a disorderly fashion to the south... they were able to explode, during and after their retreat, ground mines in the streets, by means of radio waves from Leningrad. About 60% of the houses were damaged. Afterward a control machine (transmitter) stimulated by radio waves from Leningrad was discovered and precautions appeared to have been taken."

So let's talk Polka. Not knowing what frequency or frequencies might carry the triad of death, the Finns flooded the radio band. By broadcasting strong local signals across all probable frequencies they effectively blocked the now distant Russian signal. Instead of broadcasting an empty carrier wave they went with an all-polka format. The song they played on infinite-repeat was Säkkijärven polka, also called the Karelian-Finnish Polka. It is a well-known folk tune from Finland. Of all the versions they could have selected, they went with one by the celebrity Finnish accordionist Viljo "Vili" Vesterinen.

"That polka brings past times to mind / and creates a strange longing in the chest. / Hey, musician, let the accordion play the Säkkijärvi Polka! / It takes the young and the old to dancing, nothing compares to that polka"

Odeon released Vesterinen's version of Säkkijärven Polkka ‎ in Scandinavia in 1939, (the B-side was Laivaston Tanssiaiset) and then re-released it in Finland in 1941. Viljo Vesterinen was born on March 26, 1907. He was a child prodigy, performing semi-professionally at the age of 15. Reputedly he couldn't read sheet music and played entirely by ear. He performed with the Suomi-Jazz Orchestra and the Dallapé Orchestra. He was a prolific performer and composer making about 680 recordings in his life, the earliest was with Nils Ekman in 1929 for Homokord. His later recorded for the Fenno, Electro, Decca and Odeon record labels.

But Vesterinen was also an alcoholic and in the late 1940s he began to have seizures and became paralyzed on his left side. He lost the ability to play. At the end of his life, Vesterinen worked as a tuner at the Kouvola accordion factory. In the Fall of 1955, the film Säkkijärvi Polkka premiered. It was a dramatized telling of Viljo Vesterinen's life story. Viljo even appeared in the film. He died in 1961 at the age of 54.