A young man wearing a niqab and glasses played four rounds of the Nairobi Women's Chess Open before being exposed.

"I don't think anything like it has ever happened anywhere in the world," said John Mukabi, secretary general of the Kenyan Chess Federation.

Mukabi said that after the imposter was unmasked he explained that he had done it because he had a better chance of winning the women's competition prizemoney.

The 31st Kenya Open, an international chess competition in Nairobi from April 6-10, attracted 445 participants, with 84 entries in the women's tournament.

One veiled player, silent and elusive, attracted increasing suspicion as the rounds progressed.

"The first hint that there was something wrong was when I went around with a photographer to take pictures of the competition," Mukabi told AFP on Sunday.

"When we went back to the computer to put in the names, the name was Milicent Awour. We were expecting a Muslim name. It was a bit odd but it is possible that there are people with Christian names who are Muslims."

He said match officials were also developing doubts.

"The arbiters also noticed something: after games, this person disappears and only comes back with a few minutes to the start of the next round," said Mukabi.

"Somebody also noticed that the shoulders looked more male than female... Even the rubber shoes he was wearing, they were mostly associated with men."

The mystery competitor was also scoring good results.

"The other thing is he had defeated a very experienced lady, who participated six times in the World Chess Olympiad for Kenya," said Mukabi.

After round four, the officials made their move. It was checkmate in one.

"After that game, the arbiters took him aside and one female arbiter went with him to the washrooms where he was asked to remove the hijab. On reaching there, he immediately just admitted that he was a male. He was withdrawn and the scores reversed."

"He said financial problems led him to do that," said Mukabi. "In the men's section, he had no chance at all, we had Grand Masters, International Masters..."

The young man, who is a student at the University of Nairobi, is due to appear before the Kenyan chess federation's disciplinary committee next week. He faces a suspension of several years.