Barely 17, Shirai was youngest man participating at the [[2013 World Artistic Gymnastics Championships|2013 World ChampionshpsChampionships]] in [[Antwerp]].<ref>{{cite web |url=http://rewritingrussiangymnastics.blogspot.com/2012/06/kenzo-shirai-jpn-dominates-olympic.html |title=Kenzo Shirai (JPN) dominates Olympic Hopes International, Penza |access-date=October 5, 2013 |archive-date=June 12, 2018 |archive-url=https://web.archive.org/web/20180612141751/http://rewritingrussiangymnastics.blogspot.com/2012/06/kenzo-shirai-jpn-dominates-olympic.html |url-status=live}}</ref> On FX, he qualified on top with a 16.233, 0.633 over next male, [[Diego Hypólito]] of [[Brazil]]. Shirai thus became youngest ever men’s WC FX titlist. "Historic" 22¼ twists with 7.4 difficulty score (D-score) secured the first major at only 17 years, 1 month and 11 days old. Shirai's 16.000 final total got 0.4 win-margin over American runner-up [[Jacob Dalton]]. Sport analyst [[Tim Daggett]] declared live on-air that "there is no way Shirai doesn't win this" just before Shirai began his final FX routine where he "twisted his way to first gold medal".<ref>{{Citation |last=Universal Sports (USp) |title=Kenzo Shirai Becomes Floor Champ – USp |date=October 5, 2013 |url=https://www.youtube.com/watch?v=OevKut6Ylro |access-date=June 18, 2019 |archive-date=November 4, 2019 |archive-url=https://web.archive.org/web/20191104072005/https://www.youtube.com/watch?v=OevKut6Ylro&gl=US&hl=en |url-status=live}}</ref> On VT, Shirai was again ranked on top in qualifying, but only managed to place fourth in finals.
Three of the eponymous skills for MAG got officially verified there/then in [[Belgium]] too. Shirai successfully completed the 1) '''''Shirai''''' or '''''Shirai-Kim''''' on VT ([[Yurchenko (vault)|Yurchenko]]—all VTing skills with round off [RO]–back handspring [BH] entries, originated by Soviet [[Natalia Yurchenko]] at a 1982 [[Moscow]] event—triple twist/full, or a "triple-twisting [[Yurchenko (vault)|Yurchenko]]" ["TTY"]), 2) '''''Shirai''''' or '''''Shirai-Nguyen''''' on FX ([backbwd layoutstraight] quadruple twist/full), andplus 3) '''''Shirai 2''''' on FX (forward [front] triple-twisting layout forwards).
