post-war junior high school
Refers specifically to the junior high school system established under the post-World War II educational reforms in Japan. Often used in historical or educational contexts to distinguish from the pre-war system.
The new junior high school system was launched in 1947.
中学校 is the general term for junior high school today, while 新制中学 specifically refers to the post-war system and is now mainly used in historical contexts.
Compound of 新制 (new system) and 中学 (junior high school), referring to the educational system established after World War II.