The South Manchurian Railway, commonly called “Mantetsu”, needed new locomotives to resume express train service after World War I. In 1919, six engines designed for burning lignite were ordered from Baldwin in the USA. Mantetsu gave them the name “Pashishi”, which came from the Japanese pronunciation of “Pacific”. Internally, the class was called G2, with the numbers 900 to 905. As more locomotives were soon needed, the design was improved and from 1921 23 more examples of the class G3 were produced with parts imported from Baldwin. They were given the numbers 920 to 942 and were completed by 1927. To distinguish between the different Pacific series, the G2 and G3 were combined under the class name “Pashisa”.
Although the 1919-1927 engines were quickly pushed into regular passenger service by the Pashiko class, new series were commissioned in the 1930s. They had only a few differences from the original engines, which were limited to using as many identical parts as possible with the Mikados procured at the same time. The new series were now dubbed the Pashisa class, while the older ones were renamed the Pashiha class. Between 1934 and 1940, 16 examples were built for the Mantetsu and 80 for the Manchukuo State Railway (NMR). The last 70 pieces of the MNR had a larger firebox and were called “New National Small Pashi” to distinguish them. From 1938 until the end of the war they were operated by the Japanese-controlled North China Railway.
After the Second World War, all of the Mantetsu engines were still in existence. The 29 examples of the older series were located in China and were included in the inventory of the state railway as SL4. The 16 examples of the newer series were all in Korea and later remained in North Korea, where they were probably in service until the late 1960s. Of the original 80 NMR units, the Chinese State Railways were only able to add 30 to their inventory. These were designated SL3s and distributed among several directorates in Northeast China. In 1980, twelve were still known to be in use.