Sengoku period; Warring States period (Japan, c. 1467–1568)
Refers specifically to the Japanese period of civil wars from the late 15th to late 16th century.
During the Sengoku period, many warlords aimed to unify the country.
Warring States period (China, 403–221 BCE)
Refers to the Chinese Warring States period; less common in everyday Japanese than the domestic sense.
The Chinese Warring States period ended with unification by Qin.
era of fierce competition; cutthroat times
Figurative use likening a competitive situation to the historical Warring States period.
The smartphone industry is truly in an era of fierce competition.