筆墨紙硯

笔墨纸砚
bǐmòzhǐyàn

brush, ink, paper and inkstone; Four Treasures of the Study

Wiktionary

Entry Composition

1 筆墨 bǐmò
  1. pen and ink
  2. words
  3. writing
2 紙 zhǐ classifier for documents, letters etc

classifiers: 張, 沓
3 硯 yàn ink-stone