Wan Sida 萬斯大 (1633-1683), courtesy name Congzong 充宗, style Boweng 跛翁 or Hefu xiansheng 褐夫先生, was an early Qing period 清 (1644-1911) philosopher, and brother of the more famous Wan Sitong 萬斯同 (1638-1702). He hailed from Yinxian 鄞縣 (modern Ningbo 寧波, Zhejiang) and was a disciple of Huang Zongxi 黃宗羲 (1610-1695). Wan never took part in the state examinations but lived as a private teacher.
His principle was that it was not possible to understand the Confucian Classics without studying the writings of the other "masters and philosophers". Another precondition was to perceive the shortcomings and errors in the traditional commentaries, and to explain one Classics with the help of the other texts of the canon. These teachings ran against the Neo-Confucian assumption that commentaries were more important than the proper Classics, and Wan Sida can therefore be called one of the first representatives of the philological school (Hanxue 漢學) that flourished during the early and high Qing.
Through all his life Wan Sitong commented on several books of the Classics canon, particularly the Chunqiu 春秋 "Spring and Autumn Annals" and the three ritual classics (Sanli 三禮: Liji 禮記, Yili 儀禮 and Zhouli 周禮). His studies on the Zhou period 周 (11th cent.-221 BCE) rituals are of special interest and cover various rituals from the suburban offerings to those of the local shrines, the ancestral altars and the Bright Hall (Mingtang 明堂), to issues of calendar and posthumous titles.
Wan Sitong's most important writings are Zhouguan bianfei 周官辨非, Yili shang 儀禮商, Liji oujian 禮記偶箋, Xue Li zhiyi 學禮質疑, Xue Chunqiu suibi 學春秋隨筆, Tang-Song shijing kao 唐宋石經考 (a study to the Stone Classics), and the two drafts Liji jijie 禮記集解 and Chunqiu mingbian 春秋明辨.