Nakamura, who will turn 10 on March 2 local media said, started playing the game with her father when she was three.
The previous youngest player was Rina Fujisawa, who was 11 when she turned professional in 2010.
Presented to the media on Saturday standing next to her father Shinya, himself a national champion, Nakamura said she was keen to get her first trophy.
“I feel happy when I win,” said Nakamura, who currently goes to school in Osaka. “I want to win a title while I am in junior high school."
Her father was surprised at how quickly she entered the pro ranks.
“I didn't expect she will be professional this soon,” he said.
“I think she was able to achieve this thanks to teachers who have taught her how to play Go and people that have supported her."
Go, most popular in East Asia, involves two players moving black and white stones across a square grid, aiming to seize the most territory. Its origins are said to date back thousands of years.
(Reporting by Jack Tarrant; Editing by Peter Rutherford)
