national history; Japanese history
Refers to the history of a nation, especially Japan. In Japanese contexts, it often specifically means Japanese history as an academic subject or field of study.
He is majoring in Japanese history at university.
国史の授業で鎌倉時代について学んだ。
We learned about the Kamakura period in Japanese history class.
world history
Chinese history
Compound of 国 (country, nation) and 史 (history). The reading こくし is the on'yomi of both characters.