Kōhei Uchimura
On May 19–20, 2018, Shirai competed at the lower-profile non-FIG individual all-around-only event, also at home—primarily for the Japanese coaches to help assess the level of fitness and preparation of each local gymnast hoping to be included onto the national team for namely the WC—at the 2018 NHK Trophy in Tokyo, Japan. Although it is not an event organised by the FIG, Japan still requires participation with favourable results at the competition as a prerequisite in order to be considered for the Japanese team at the next WC. If an athlete had to miss the event but still want represent Japan then, he or she must secure a waiver, which is rarely granted. Shirai won the silver medal here with a combined score of 257.895 including floor’s top score of 15.433 as well as third highest of 14.833 on vault, just behind Takumi Sato competing only on floor, rings and vault, and vault specialist Hidenobu Yonekura competing only on his one specialty apparatus. For Shirai's other events, those scores were 13.600 on pommel horse, 13.366 on rings, 14.433 on parallel bars, and 14.066 on high bar respectively. Gold medal went to the legend Kōhei Uchimura, who had come from behind to win with the combined total of 258.629, which also included the top score (14.966) on high bar, and second highest (14.633) on floor.