Former women's world No. 4 Kimiko Date said Monday she will retire from competitive tennis after next month's Japan Women's Open in Tokyo.

The 46-year-old, who retired once in 1996 and made a comeback in April 2008, wrote on her official blog that she has been far from top form and playing with pain in her knee and shoulders.

"Kimiko Date has decided to put an end to her second challenge," she said. "I was determined to continue my challenge until the day I could no longer ignore my inner voice."

Date underwent a second surgery on her left knee in April last year, but has been unable to dismiss injury concerns, saying she has being feeling a wide gap between where she would like to be and where she is in reality.

"I am now concentrating all my energy in rehabilitation, training, and practice towards The Japan Women's Open while taking daily consideration of my knee and shoulder condition," Date said, referring to the Sept. 11-17 meet at the Ariake Tennis Forest Park.

"This tournament in Ariake will be my last tournament of my second challenge. Now that I have made the difficult decision to retire, I would like all of you who have supported me over the years to come and see my final play and it would make me very happy if you could keep that image in your memory."

Date reached the singles semifinals in three of four Grand Slams -- the Australian Open, the French Open and Wimbledon. She placed fourth in the world in November 1995 for her highest singles ranking, and has won eight WTA Tour titles to date.

Date, who turned pro in 1989, won her first title in 13 years at the Korea Open in 2009 and returned to competition in May after a 16-month injury layoff, only to have her hopes of taking part in the recently concluded U.S. Open qualifying rounds dashed because of shoulder pain.