What were the flags outside those shops in the Song Dynasty? I remember a special name.

The wine flag in Song Dynasty is also called wine hope, wine curtain, green flag, brocade fork and so on. As one of the oldest forms of advertising, wine flag has a long history in China. "Han Feizi" records: "There were wine sellers in the Song Dynasty ... the flag was held high." A "flag" is a wine flag. Later generations said: "The wine market has flags, which were first seen in some places.