A series of four games pitting chess grandmaster Garry Kasparov against a computer has ended in a draw.
Kasparov moved the pieces using voice commands
Kasparov drew the fourth and final game of the Man v Machine clash in New York, leaving himself and the computer with an overall score of two points each.
Kasparov tied his first game against the X3D Fritz computer programme, lost the second, and won the third.
He wore virtual reality glasses, moving the pieces using voice commands and using a joystick to rotate the board.
The fourth game was declared a draw after 27 moves.
Kasparov will now collect $175,000. He would have got an extra $25,000 for beating the computer.
Kasparov, 40, has played computers before, beating IBM's Deep Blue machine in 1996, but losing a rematch to an upgraded version a year later.
Earlier this year, a series of six games with the Israeli Deep Junior chess program ended in a draw.
Mr Kasparov - who became the youngest world champion at 22 years of age in 1985 - is the top-ranked chess player in the world.
However, he lost the world champion crown to his countryman Vladimir Kramnik in 2000.