Former women's world number one golfer Ai Miyazato of Japan reacts as she attends a news conference to announce her retirement in Tokyo, Japan. Photo: Reuters/Issei Kato

Former women’s world number one Ai Miyazato said on Monday that a crisis of confidence triggered her decision to retire from professional golf at the end of the current season.

The Japanese 31-year-old, a nine-time winner on the American LPGA circuit, admitted her struggles dated back to 2012, when she claimed her last tournament victory.

“It was getting harder and harder to stay motivated,” a tearful Miyazato told a news conference in Tokyo.

“That was partly to do with having reached the top of the rankings,” added the Okinawan-born sensation, who has been tormented by her failure to win a major.

“I went to a mental coach and tried to rediscover my old focus but it just wasn’t there.”

Miyazato’s decision comes just a week after world number 10 Jang Ha-na dropped her LPGA Tour membership and returned home to South Korea to be nearer her family.

The 25-year-old from Seoul won US$2.6 million and four titles since joining the LPGA in 2015.

She plans to return next month to the LPGA of Korea Tour, where she won eight times and topped the money list in 2013.

Former women’s world number one golfer Ai Miyazato of Japan bows as she leaves a news conference to announce her retirement in Tokyo. Photo: Reuters/Issei Kato

Miyazato – the younger sister to Kiyoshi and Yusaku who play on the Japanese men’s tour – won a Japanese title as an amateur in 2003 while still at high school.

She followed that with an astonishing rookie season in 2004, capturing five more domestic titles, and going on to win 15 times on the Japanese tour.

Her switch to the lucrative LPGA Tour in 2006 proved equally successful and by 2010 she had risen to the top of the women’s rankings.

“I achieved more than I ever thought possible,” said Miyazato, who has slipped out of the world’s top 100, her troubles compounded after suffering from the dreaded yips with the putter.

“But I don’t think I have the tools to keep competing. Even when I was winning tournaments I began to worry about not being able to win a major.”

She added: “I lost my way and it was really difficult to get back on track.”

Miyazato, who started playing golf at the age of four credits her father Masaru Miyazato as the individual who has most influenced her career, according to the Ladies Professional Golf Association.

She has nine LPGA tour victories in her career: the 2009 Evian Masters, the 2010 Honda PTT LPGA Thailand, the HSBC Women’s Champions, Tres Marias Championship, ShopRite LPGA Classic, Safeway Classic all in 2010, the 2011 Evian Masters, and in 2012 the LPGA LOTTE Championship and the Walmart NW Arkansas Championship.

This year she has struggled, with her highest finished tied at 34 in the LOTTE Championship on April 12. Out of the four other LPGA tournaments she has played this year, she has finished at or above 40th place and missed the cut once.