At only 15 years old, the Japanese already has the world at his talented fingertips.
The table tennis star sprung to global fame last year, by becoming the youngest ever winner of an ITTF World Tour men’s singles title by clinching the Czech Open title at the tender age of 14 years and 61 days.
Winning silver in the men’s singles at YOG could be a foreshadowing of even greater success to come at Tokyo 2020.
So who is this emerging teen sensation?
Table tennis roots
Harimoto was born in Sendai, the same place as figure skating superstar Yuzuru Hanyu, on the 27th June 2003.
Table tennis is in his DNA, as both his Chinese parents, Yu and Ling Zhang were professional players.
Father Yu was a coach at the Sendai City Table Tennis Centre, whilst his mother Ling once represented China at the World Championships in 1995.
Little wonder then that as soon as he could walk, young Tomokazu was also holding a bat.
His progress was startling. At only three years and four months, he finished fourth in a local competition organised for under 8s.
By the time he was seven, Harimoto was a national champion.
Two years later, he took part in the Junior Boys Singles at the Japanese Championships – facing down players twice his age across the table.
Whereas others might be fazed or intimidated, playing against more experienced opponents only served to increase Harimoto’s desire to win. After all, the bigger they come, the harder they fall.
In October 2015, history was made at the Polish Open in Warsaw as Harimoto became the youngest ever player to reach the first round of an ITTF World Tour men’s singles event.
At the tender age of 12, the Japanese took on none other than reigning Olympic champion Ma Long in the round of 32.
On this occasion, Harimoto was easily brushed aside – but had served notice of what was to come.
In 2016, right before his 13th birthday, the prodigy claimed the under-21 Japan Open title. The youngest player ever to do so.
The singles title at the World Junior Championship belonged to him later that year; but by now, Harimoto was ready to mix it with the big boys.
Move to Tokyo
His win at the World Juniors came after Harimoto had made a big decision in his life.
After graduating from elementary school in his native Sendai in April 2016, he opted to uproot and move to Tokyo.
There he enrolled in the Japanese Olympic Committees ‘Elite Academy’.
The Academy is designed to help nurture the country’s top talents reach their full potential in both sport and education.
For Harimoto, his choice soon started paying dividends.
2017 started with a head-turning performance at the India Open.
Harimoto reached the final, falling only to the defending champion Dimitrij Ovtcharov after swatting aside a succession of senior players along the way.
In June, Japanese team mate – and Rio 2016 bronze medallist - Jun Mizutani became another notable victim as Harimoto made his World Championship debut.
The then-13-year old reached the quarter-finals in Dusseldorf, and followed it up by advancing to the the semis at the China Open.
But it was on 27th August 2017 when Harimoto truly created history.
At 14 years and 61 days of age, the Japanese became the youngest ever player to win a men’s singles title at the Czech Open in Olomouc.
Harimoto defeated German superstar Timo Boll to secure his maiden crown, but straight away set his sights further ahead.
“At the Tokyo 2020 Olympic Games I want to win the men’s singles and Men’s team gold but I know I must practise hard” the youngster said immediately after his triumph.
The records continue to be rewritten.
This year began with Harimoto becoming the youngest ever Japanese national men’s singles champion (at 14 years and 207 days).
More major names have fallen prey to the prodigy: Fan Zhendong defeated at the Asian Cup in April; then Ma Long conquered in front of his home fans at the Japan Open last June.
It was perhaps his most glorious moment yet.
A second ITTF World Tour title would be claimed in Kitakyushu as the Japanese teenager defeated Zhang Jike in the final.
Buenos Aires and beyond
Long before the Youth Olympic Games Harimoto had already set out his targets: gold in the men’s singles and team events.
Few would predict any other outcome.
Harimoto cites his aggressive backhand as his biggest weapon.
But for most observers, his greatest asset his his steely determination.
There is an unshakeable inner-self belief that rests deep inside Harimoto.
A belief that is taking him to a glorious, golden future.