Battle of Motien Pass
1904 CE.
Shown on the map at 40.000°, 122.500°.
The Battle of Motien Pass was a minor land battle of the Russo-Japanese War, fought between the Imperial Japanese Army under General Kuroki Tamemoto and the Imperial Russian Army under General Fyodor Eduardovich Keller over control of a strategic mountain pass on the main road between the coast and Liaoyang in Qing China on 10 July 1904.
Text from the Wikipedia article Battle of Motien Pass, licensed CC BY-SA 4.0.