Japan Railways locomotive numbering and classification

This page explains the numbering and classification schemes for locomotives employed by the Japanese Government Railways, the Japanese National Railways and the Japan Railways Group. == Steam locomotives == === Pre-nationalization === Prior to the nationalization of Japanese railways in 1906 and 1907, the government-run railways had numbered their steam locomotives only with serial numbers without consideration of the types of the locomotives.

Source: Wikipedia — Japan Railways locomotive numbering and classification (CC BY-SA 4.0)