By 1941,one quarter of this country was under japanese control

China

Explanation:

By 1941, Japan held most of the eastern coastal areas of China, which amounted to one quarter of this country. This was a consequence of the Second Sino-Japanese War. This was a military conflict that was fought between the Republic of China and the Empire of Japan from 1937-1945. During this war, China was aided by the Soviet Union and the United States. After 1941, this war was combined with the many other conflicts that were taking place around the world due to World War II.

considered the turning point in pacific war. the japanese tried to lure the american navy out so it could be destroyed but failed. the americans were led by admiral chester nimitz. the victory by america would put them on the offensive for the remainder of the war.