is a Japanese male table tennis player. He is the gold medalist at the 2010 Youth Olympics and he won the World Junior Table Tennis Championships in 2010 (doubles) and 2011 (singles).
On 21 April 2012, he defeated Ma Long of China, World Rank no 1, to become the first player to be qualified for 2012 Olympics from the Asian Olympic Qualifiers.
Since 2012 he has been playing for the German Team TTC matec Frickenhausen.
He won the 2014 Russian Open singles title.
Career
Junior career
Niwa had a prolific junior career beginning in 2008. He reached the quarter-finals at the 2008 India Junior Open in Pune, India, and won the doubles title with his partner Yuki Hirano. At the 2008 World Junior Championships in Madrid, Spain, he partnered with Kenta Matsudaira to reach the semi-finals. The following year, Niwa partnered with Asuka Machi to win the 2009 ITTF Cadet Challenge and ITTF Junior Circuit Finals in Tokyo, Japan.
At the 2009 World Junior Table Tennis Championships, Niwa reached the quarterfinals in the men's singles event before being defeated by Lin Gaoyuan. Niwa qualified for the 2009 World Table Tennis Championships in Yokohama, Japan by defeating Josef Simoncik in the qualification tournament. Niwa reached the round of 64 before being defeated by Germany's Dimitrij Ovtcharov.
At the 2010 Singapore Youth Olympics, he won a gold medal in the Boys' Singles Event, and a gold medal partnering Ayuka Tanioka in the Mixed team event. Niwa won the U21 title at the 2011 Dortmund Pro Tour German Open by defeating Kim Min-seok. At the 2011 Incheon Pro Tour Korea Open, he defeated Jeoung Young-sik to obtain his second U21 title that year. At the 2011 Manama World Junior Table Tennis Championships, he won the gold medal in the men's singles event, defeating Lin Gaoyuan of China.
2012: Breakthrough
By 2012, the 17-year-old world junior champion was gaining widespread attention. His breakthrough came at the 2012 Asian Olympic Qualification Tournament where he overcame world ranked No. 1 Ma Long and became the inaugural Asian player in the sport to qualify for the Olympics. Partnering with Kenta Matsudaira, Niwa overcame the Chinese pair of Wang Hao and Zhou Yu to win the 2012 World Tour Polish Open doubles title.
2013
Niwa qualified for the 2013 World Table Tennis Championships seeded 15. He reached the fourth round in the men's singles event before being defeated by Ma Long. He partnered Kenta Matsudaira in the doubles event and reached the third round before losing to compatriots Jun Mizutani and Seiya Kishikawa. At the 2013 World Tour Japan Open in Yokohama, the Niwa/Matsudaira pair lost in the finals against compatriots Jin Ueda and Maharu Yoshimura.
2014: First ITTF World Tour Title
At the 2014 World Team Table Tennis Championships in Tokyo, Niwa won 4 out of his 5 matches, contributing to Team Japan's bronze medal. At the 2014 World Tour Grand Finals in Bangkok, the Niwa/Matsudaira pair lost in the final to Korean pair Cho Eonrae and Seo Hyundeok. Niwa won the 2014 World Tour Russian Open title in the men's singles event, defeating England's Paul Drinkhall in the final. The Niwa/Matsudaira pair competed in the semi-finals and were defeated by the Russian pair Fedor Kuzmin and Grigory Vlasov.
2015
At the 2015 World Table Tennis Championships, Niwa reached the 4th round before being defeated by China's Fan Zhendong. In the doubles event, the Niwa/Matsudaira pair reached the semi-finals, and were defeated by Fan Zhendong and Zhou Yu. This was the last international partnership with Kenta Matsudaira.
2016
At the 2016 World Team Table Tennis Championships in Kuala Lampur, Niwa contributed to Team Japan's success in winning the silver medal. The team lost to Team China in the final. Niwa represented Japan at the 2016 Summer Olympics in the men's singles event. He reached the quarterfinals before being defeated by eventual silver medalist Zhang Jike. In the Men's team event, Niwa contributed to team Japan's first silver medal in the category. However, Niwa expressed discontentment with his performance, not winning any singles matches.
