History
According to Elfverson & Co, the story began in 1926, when Gosta Elfverson started a company in England importing and selling Swedish glass. He received a yo-yo and had the idea of making them with his brother Olof Elfverson in Sweden, who owned Elfverson & Co. At first the yo-yo was made in glued parts; a few years later the foreman Ivan Pettersson devised a way to turn it from a single piece, and the Kalmartrissan has been made in roughly the same way since 1932.
The yo-yo carries a foil-stamped print of Kalmar Castle on one side; early examples were pad-printed with a different logo, and the body was later slightly flattened to improve the print. The first yo-yos had a 1.7 mm gap, because string was thinner then. The gap was widened to 2.2 mm in a redesign, and to 2.8 mm in 1999 after competitors in the USA reportedly sanded their yo-yos to enlarge the gap. Elfverson says about 20,000 are made per year today, versus over a million yo-yos made for Parker Brothers in Canada in a single year in the 1970s. In the USA and Canada it was known as the Sweden Yo-Yo because of the Sweden marking on the back.
