On June 21–23, 2019, Shirai competed at the 2019 All-Japan Apparatus Championships in Takasaki, Japan, hoping he would do well enough to secure a spot on the Japanese national team, and compete at the 2019 Artistic Gymnastics World Championships in Stuttgart, Germany. It was ultimately not meant to be his year though. Shirai had qualified into the individual event finals specifically on floor exercise, vault and the horizontal bar in second, fourth and sixth respectively. In these finals, he had finished in third (14.900), fifth (14.433) and eighth (11.200) place, respectively for each of these three apparatuses too. Finishing ahead of Shirai on floor exercise were Kazuki Minami with a total score of 15.033, and Naoto Hayasaka with a total score of 15.000. Their top finisher on vault was Keitoro Okubo, posting the average combined score of 15.233, and the winner of the horizontal bar was Hirohito Kahama with a total score of 14.766. Shirai's floor D-score numbers had remained on top among all the finalists. However, his execution needed some additional work, and could have been cleaner, which was thus reflected on the routine's E-score. Shirai's vault D-score values were comparatively lesser—only one with the lowest 5.2—and needed higher base numbers before he could seriously challenge the top vaulters.