Set against the events of the Finnish Continuation War, the film follows a machine gun troop's journey into the Soviet Union. The troop includes the simple-minded Hietanen, the jokey Vanhala, the cynical Lahtinen, the cowardly Riitaoja and grumpy Lehto. The film also follows the commanding officers, such as the happy and slightly senile Captain Kaarna, the young and idealistic 2nd Lieutenant Kariluoto, the calm and modest 2nd Lieutenant Koskela and the strict and unsympathetic Lieutenant Lammio.
They face many struggles, such as seeing the supportive Kaarna die in their first battle, three of the soldiers refusing to leave their punishment post during an air-raid as well as defending the trenches after the Finns have taken back parts of Karelia. Part of the way, the troop is joined by Rokka, a Karelian veteran of the Winter War, who also clashes with Lammio due to having little respect for military discipline despite being an excellent and capable soldier.
Throughout the film several of the main characters die. Lehto is injured during night-patrol, left behind and shoots himself. Riitaoja dies the same night when he runs off frightened and gets lost in the woods. Lahtinen dies during the winter, defending his position as his fellow soldiers flee. Hietanen becomes blinded when he saves a young serviceman from being shot. His military ambulance crashes and the blinded Hietanen is gunned down by passing Russian planes while trying to save the other injured soldiers. Kariluoto dies while leading a counter-attack, and shortly afterwards Koskela gets shot while destroying a tank using a satchel charge.
The film began production and was released only a year after the release of the novel. There had been immediate competition for film rights, which were won by SF Film, led by T. J. Särkkä; Linna received one million Finnish marks in the deal.[1][5] Filming began in April 1955 in Nurmijärvi, although the final script was not finished until the end of May.[1]
The film is relatively loyal to the original novel, though the Soviets are rarely shown in most of the scenes. Kariluoto's death is different from the novel, though his last words are the same. Lammio's come-uppance from a disrespectful soldier during the Finns' retreat is absent from the film. The character Karjula has been omitted entirely.[6] The role of Rahikainen has also been downplayed considerably; in the novel he is Hietanen's closest friend but merely a supporting character in the film.
Due to disagreements with SF Film, the Finnish Defense Forces refused to assist with the filming.[5] Thus all soldiers are actors and there is a heavy use of stock footage in several scenes where Finnish artillery is shown.[1]
As the soldiers are played by SF Film regulars,[1] most are physically much older than their characters in the novel. Several actors were considered for the role of Rokka but were ultimately rejected because they couldn't deliver his Karelian Finnish dialect. Reino Tolvanen was an actual veteran of the Continuation War, having served in the air force, and was cast due to speaking the dialect naturally.[7]
Edvin Laine and Väinö Linna became good friends during the production. Laine would go on to make several more films based on Linna's novels after the mid-1960s, when SF Film had gone bankrupt.
Upon completion, The Unknown Soldier was the longest and most expensive film in the Finnish cinema history up to that point: 181 minutes and, according to the account book, FIM 46,667,761.[1][5]
At the beginning and the end of the film Finlandia, by Finnish national composer Jean Sibelius, is played.[8] The music used in the film is a mixture of original music composed by Ahti Sonninen and stock music.[9]
"Tuntematon sotilas". Elonet (in Finnish). Kansallinen audiovisuaalinen instituutti. Retrieved December 23, 2021.