TOKYO—Daiki Hashimoto kept Japan’s grip on the Olympic men’s gymnastics all-around crown in breathtaking style on Wednesday, leaving the few watching inside Ariake arena roaring and a bitter China filing an inquiry. With the host nation’s “King” Kohei Uchimura, Olympic all-around champion in 2012 and 2016, choosing not to defend his title in Tokyo, it was left to his heir apparent Hashimoto to step up. The 19-year-old did not disappoint, posting a winning point total of 88.465 to push China’s Xiao Ruoteng, the 2017 world all-around champion, into second place. Russian Nikita Nagornyy, the reigning world all-around champion, took bronze. Going into the final rotation with Xiao leading and all the medal contenders finishing on the high bar, the gold had looked headed back to China for the first time since the 2008 Beijing Summer Games. But then Hashimoto, the last man to compete, produced a spectacular routine that earned …