A trendy internet variant of 指南 ('guide,' lit. 'point south'). Bilibili and Zhihu users flipped the direction to 指北 partly as wordplay, partly because compasses in physics class point north — now widely used in titles like 入门指北 ('beginner's guide').
history
The classical word 指南 dates to the south-pointing chariot 指南车 of pre-Qin legend. 指北 is post-2010 internet coinage that piggybacks on that template.
