I joined the convention about 7 years ago. (日本)SF大会 is the major event held every year, and we in general call it SFコン among my peeps. コン is the abbreviation of コンベンション (convention). Unfortunately, no one understands what the heck it is, so we have to explain it as コミケのSF版 (SF version of Comiket). Comiket, also known as Comic Market, is the word-famous nerdy event for comics and animations. I bet you’ve heard of it before.