Ikee later said that the tactics employed had been "a mistake", commenting "this colt is big and has long limbs and he’s not able to take small steps". On 29 May, in front of a 140,000 crowd at Tokyo Racecourse, Satono Diamond was one of eighteen colts to contest the 83rd running of the Tokyo Yushun and started second favourite behind Dee Majesty. He was positioned several lengths behind the early leaders before moving up to dispute the lead in the straight but in a very close finish he was beaten a nose by Makahiki with Dee Majesty half a length away in third place. After a break of almost four months, Satono Diamond returned to the track in the Kobe Shimbun Hai (a major trial race for the Kikuka Sho) over 2400 metres at Hanshin on 25 September. He started the 1/5 favourite in a fifteen-runner field an won by a neck from the 26/1 outsider Mikki Rocket. Ikee commented "that was his first outing in a while and he was a bit keen and also didn’t show his best in the finish either. Still, he won, so that’s the important thing." In the 77th running of the Kikuka Sho over 3000 metres at Kyoto on 23 October Satono Diamond started the 1.3/1 favourite in an eighteen-runner field which included Dee Majesty, Mikki Rocket and Air Spinel. He after racing in midfield he moved up on the outside entering the straight, took the lead 200 metres from the finish and quickened clear to win the race by two and a half lengths from the outsider Rainbow Line. After the race Lemaire said "I’m excited and happy to be able to win a classic race for the first time in Japan. The colt was in his best condition and the only concern was the distance. But he responded really well in the last stretch so I was quite confident that we will win. He’s a top-class horse and will definitely be able to win other G1 races". On 25 December Satono Diamond was matched against older opposition when he was one of sixteen horses invited to contest the Arima Kinen over 2500 metres at Nakayama. He was made the 2.6/1 favourite ahead of the four-year-old Kitasan Black and the 2015 winner Gold Actor. The other runners included Sounds of Earth (second in 2015), Cheval Grand (Hanshin Daishoten, Copa Republica Argentina), Marialite (Queen Elizabeth II Cup, Takarazuka Kinen) and Mikki Queen (Yushun Himba, Shuka Sho).