Both Nintendo and Sega formally enter the video game console market with the Famicom and the SG-1000, respectively, in 1983.
I'm honestly surprised that English speaking circles don't acknowledge this, given the historical importance of these systems' releases. Japanese circles tend to celebrate today, but tellingly, only as Famicom Day. Let it be known that Nintendo has been monopolizing public video game nostalgia through the Famicom/NES for a while now.