The Sino-Japanese War occurred in two phases:
The First Sino-Japanese War was fought between China and Japan from 1894 to 1895.
The Second Sino-Japanese War was fought between China and Japan from 1937 to 1945, which was a part of World War II.
If you're referring to the first Sino-Japanese War, it occurred from July 25, 1894, to April 17, 1895.