The JGR Class 2120 was a B6 type 0-6-2 steam tank locomotive used on Japanese Government Railways for shunting and pulling freight cars.

[1] During the Russo-Japanese War, the Imperial Japanese Army captured the southern portion of the Russian-owned Chinese Eastern Railway.

However, in 1908, Mantetsu completed the conversion of its lines to standard gauge, rendering these locomotives useless.

Five were sent directly to the Taiwan Government Railway, and the rest were returned to Japan.

The Taiwan Government Railway eventually received a further ten, where they became class CK80.