Yeah, it dates back to 1949. Shortly after the sino-japanese war on the 1st of October 1949 the CCP announced the creation of the People's republic of china.
The Japanese were all like, LOL, that's our empire why do you say it's a country and it became tradition to make outlandish jokes on the 1st of October. So to this day when the PRC celebrate their national day Japan celebrate jokes day (冗談の日).