| KuMoHa 12 | |
| Service: | 1933–2002 |
| Refurbishment: | 1933,1950,1958,1960, 1987 |
| Operator: | JGR (1933–1949) JNR (1949–1987) JR East (1987–1996) JR Central (1987–2002) |
| Lines: | Various |
| Numberbuilt: | 27 vehicles (all converted from other train types) |
| Numberservice: | none |
| Numberpreserved: | 1 vehicle |
| Carbody: | Steel |
| Carlength: | 17000mm |
| Doors: | 3 per side |
| Traction: | Resistor control |
| Traction Motors: | MT15 |
| Transmission: | Camshaft |
| Collectionmethod: | overhead catenary |
The was a class of electric multiple unit (EMU) railroad cars formerly used by the Japanese National Railways (JNR). These are EMU power cars of 17meter length with a driver's cab at each end, three passenger doors on each side, and lengthwise bench-type passenger seating. The cars themselves were built in the later 1920s and 1930s for JNR's predecessor, the Japanese Government Railways (JGR), but the class, originally named, was established on 1 June 1953 by a JNR revision of its rolling stock classification regulations. In June 1959, a new JNR classification revision assigned the code to all cab-equipped power cars, giving the KuMoHa 12 class its present name.
When the MoHa 12 class was formed in 1953, it consisted of 13 cars of the old JGR dual-cab class. Over time, additional cars were added by remodeling related old JGR classes, for an eventual total of 33 cars.
The various KuMoHa 12 cars have the following origins: