Learn What You Lack, Retain What You Know — Learning Needs Maintenance

In the Zi Zhang chapter of the Analects, Zixia says, “Each day, learn what you do not yet possess; each month, do not forget what you have already mastered. Then you may be called a lover of learning.” Here, the character wang is read as wu, meaning what one does not yet have, while “what one can do” refers to knowledge or ability already acquired. Zhu Xi’s commentary quotes Yin Tun’s neat summary: renew yourself daily without losing what you have gained.

It is easy today to let new material dictate the pace of learning. Whether we are reading, practising the piano or learning software, encountering the unfamiliar matters; but if an older ability is no longer used, it may never become dependable. The line is not a demand for mechanical daily streaks. It reminds us that genuine accumulation involves both exploration and maintenance.

Source text: https://ctext.org/analects/zi-zhang/zh
Commentary: https://zh.wikisource.org/wiki/%E5%9B%9B%E6%9B%B8%E7%AB%A0%E5%8F%A5%E9%9B%86%E8%A8%BB/%E8%AB%96%E8%AA%9E%E9%9B%86%E6%B3%A8%E5%8D%B7%E5%8D%81