the Four Books and Five Classics of Confucianism
Refers to the canonical texts of Confucianism: the Four Books (四書) and the Five Classics (五経). A yojijukugo used in historical and philosophical contexts.
The Four Books and Five Classics were once required reading for Confucian scholars in China and Japan.
Refers specifically to the Four Books (大学, 中庸, 論語, 孟子), a subset of the 四書五経.
Refers specifically to the Five Classics (易経, 書経, 詩経, 礼記, 春秋), the other subset.
From Chinese 四書五經 (Sìshū Wǔjīng), a compound of 四書 (Four Books) and 五経 (Five Classics).