Between 1934 and 1944, the Mantetsu in South Manchuria got a number of Mikado locomotives which were called “Mikaro”. To burn the lignite found in Korea, they got a larger grate than previous locomotives. They had many common parts with the Pashisa and Puresa and were built by different Japanese manufacturers. Also the Manchukuo National got a total of 171 locomotives of the same design that they called “Small Mika”. They had a regauging device for a possible future war with Russia so that they could also be used on Russian broad gauge tracks. As another preparation for a war, the Kwantung Army in Manchuria ordered a prototype with a condensing tender in 1941. This one was called “Mikaku”, but remained a one-off.

At this time, all these locomotives, together with the Mantetsu's Mikasa, were grouped under the name Mikaro. After World War II, China Railways took over most of these locomotives and designated them JF6. They even built more locomotives of this type at Shenyang and the US military ordered five for the South Korean state railway in 1947 from Kisha Seizō. So in total, around 475 locomotives of this type had been completed by 1959. Over the years, some also came to North Korea and Vietnam.