The SG-1000 is Sega's first attempt at a video game console. Because it failed in all aspects, Sega dropped it fast and moved on to make the more successful Mark-III, and because of this it's game library is relatively small. The main problem with the SG-1000 was it's controller: it was clunky and unresponsive, and replacing it was a huge headache, since it was hardwired into the console.
This one is so obscure, the only country outside of Japan that received it was New Zealand. It has some variants, like the Othello Multivision.