They were originally built for the South Manchuria Railway (Mantetsu) to pull the Asia Express[1] - Mantetsu's signature train and most iconic locomotive, whose images were used on fliers, posters, postage stamps, and even children's school textbooks, as a symbol of technology and modernism in Manchukuo and was used to demonstrate the success of Japan's imperial project.

[2] After designing his first locomotive, the Pashiko class, at age 37 Nobutarō Yoshino (吉野信太郎), who had studied at the American Locomotive Company for two and a half years and, as the young star of Mantetsu's engineering division, nicknamed "King of Locomotives",[3] designed the streamlined Pashina class was built with the specific purpose of hauling the long-distance, high-speed Asia Express limited express train between Dalian and Xinjing (Changchun), at speeds up to 120 km/h (75 mph).

[1] It was one of the world's first steam locomotives to be fully streamlined,[4] which reduced air resistance by 30%,[3] and they were painted a distinctive Prussian blue colour.

[3] They were the first Mantetsu locomotives to be fitted with the Schmidt type E superheater, and were also equipped with a combustion chamber firebox, a feedwater heater, and an automatic stoker; the stoker was deemed essential, as it was calculated that human power could not supply the necessary quantities of coal fast enough.

[4] After experiments in the Kawanishi Aircraft Company's wind tunnel, the shape of the streamlining was redesigned, and the final unit, number 981 (later パシナ12) was built with the new design by Kawasaki in 1936.