The Chi­nese film­mak­er Wang Bing’s ‘Til Mad­ness Do Us Part, a doc­u­men­tary about a men­tal insti­tu­tion in Yun­nan, runs three hours and 48 min­utes. Beau­ty Lives in Free­dom, on the life of impris­oned artist Gao Ertai, is five and a half hours long; Dead Souls, on the sur­vivors of a hard-labor camp in the Gobi Desert, eight hours and fif­teen min­utes. Even if you know noth­ing else of his work, you may get the impres­sion that Wang isn’t the most shame­less­ly com­mer­cial of film­mak­ers. The extreme dura­tion of some of his movies sure­ly make them a hard sell, as do his grim choic­es of sub­ject mat­ter. But if you want to under­stand the trans­for­ma­tion of mod­ern Chi­na, you could hard­ly find a rich­er body of cin­e­mat­ic work. In the video essay above, YouTu­ber Ken Dai extols the virtues of Wang’s first film: Tie Xi Qu: West of the Tracks, whose more than nine hours of footage depict the last years of the tit­u­lar indus­tri­al dis­trict of Shenyang. Wang draws them from the more than 300 hours …