He won the silver medal in the men's 1500m freestyle at the 2014 Asian Games.

[2] Kohei won the gold medal in the 800 meter freestyle, with a time of 7:49.96, two seconds faster than 2nd place finisher, Sergii Frolov.

At the 2014 Japan Open, Kohei set a national record in the 1500 meter freestyle, clocking 14 minutes and 54.80 seconds.

[5] At the 2014 Asian Games, Kohei placed fourth in the 400 meter freestyle, with a time of 3:51.09.

Later, he went on to win the silver medal in the 1500 meter freestyle, with a time of 14:54.86, five seconds slower than 1st place finisher Sun Yang.