Few small European countries were as lucky as Sweden in the 20th century. It and its Scandinavian neighbours avoided participation in the First World War. During the Second World War, while even that quiet corner of Europe was drawn into the fighting, Sweden managed to retain its neutrality despite war coming at it from all sides. Denmark was occupied, Norway became a battlefield for British, French, and German forces, the Soviet Navy and the Kriegsmarine clashed in the Baltic, but Sweden lived in peace.
Of course, it's hard to explain everything with pure luck. Swedish neutrality was held up in part by careful work of diplomats. The aspect of sitting out in a war against fascism is beyond the scope of this article, but the Swedes still knew of the rule laconically described by Napoleon Bonaparte: "A nation which won't feed its army will soon feed someone else's."
Sweden is an average country in size, but low in population. The wealthy and prosperous Sweden we know in the 21st century was not exceptional in the middle of the 20th. Nevertheless, despite a shortage of human and material resources, Sweden paid close attention to military matters ever since announcing their neutrality in 1814. As a result, the country with only 10 million people (about the same as Belarus, Portugal, Greece, or Serbia) produced and keeps producing a wide variety of infantry weapons, armour, artillery, and aircraft. From 1945 to the end of the 1950s, Sweden was developing nuclear weapons and carriers for them: bombers and winged rockets.
The nature of neutrality caused a significant amount of Swedish weapons to be developed witout looking at foreign developments. In some cases, weapons developed by Swedish engineers or foreigners working in Sweden became objects of imitation for foreign designers. One example of this is the Lansdverk L-60 tank, which served as the base model for the Stridsvagn m/38 tank and the Hungarian Toldi light tank. The L-60's torsion bar suspension used in 1934 became the norm in worldwide tank building much later. The first Soviet mass production tank with torsion bars was the T-40, which was created in 1939.
The same L-60 with its revolutionary suspension could be considered a precursor of the last Swedish turreted tank, the Stridsvagn 74.
The L-60 design became the foundation of the Stridsvagn m/38, m/39, m/40L and m/40K which formed the core of the Swedish tank park until 1944 and served abroad after the war (25 Strv m/40L tanks were sent to the Dominic Republic in 1956). Tanks of this family weighed about 9 tons, were armed with 37 mm guns, and were equipped with 142 and 162 hp engines.
Towards the end of the 1930s, the Swedes developed the medium Lago tank for the Hungarian army, which had a certain similarity to the L-60 and its "offspring". The 15 ton tank armed with a 47 mm gun was finished and shown to the Hungarians, but they chose the simpler Czechoslovakian T-22 tank as the basis for their Turan. However, the work on the tank was not wasted. In the early 1940s, the Swedish army experienced a need for medium tanks. The Lago served as a basis for the Strv m/42 tank with a mass of 22.5 tons, a short barreled 75 mm Bofors gun and four 8 mm machineguns.