The X Tournament Series, often shortened simply as X, was an online tournament series, founded by Doqtor Kirby, and built upon by the Super Smash Flash 2 community. The X Tournament Series ran a total of 23 events (27 counting Q Tournament Series events, and 30 counting the three one-shot events after its conclusion): eighteen monthlies, one annual event, and four qualifiers. The X Tournament Series was discontinued after its fifth monthly event in the 2016 Season.