In China, electrification with 25,000 V alternating current was strongly promoted in the 1980s. Since it was found that there was a technological deficit in terms of electric locomotives and that the existing engines had reliability problems, the search for suitable models began abroad. As a result, 85 six-axle 6Ks were imported from Japan, 100 eight-axle 8Gs based on the ВЛ80 from the Soviet Union and 150 eight-axle 8Ks from France.

The 6K was a Hitachi locomotive with three two-axle bogies. This design had already been used successfully in Japan in the past. Thanks to a center bogie that was laterally adjustable by 230 mm, this resulted in a good ability to negotiate curves and caused little wear on the rails. The special feature of the power transmission was that it consisted of only two groups and the two axles of the middle bogie were each driven by one group. Compared to the Japanese locomotives with a B-B-B wheel arrangement in cape gauge, the 6K not only had a larger gauge, but was generally significantly larger and heavier.

Although the 6K could only do 100 km/h, it was used equally for passenger and freight trains. As expected, it achieved better availability than the electric locomotives previously manufactured in China. In the nineties it was further developed into the SS7, which was built until 2007. By 2010, only four 6Ks had been retired. Since their reliability subsequently decreased and enough new-generation locomotives were already available, the large wave of retirement began in 2013. The last use of a 6K was on March 21, 2014 and today one engine remains in the museum in Beijing.