So infuriated was Napoleon Bonaparte, by some accounts, that the short-fused French emperor knocked the pieces from the chessboard midway through a match, humiliated by his impending defeat. It was outrageous that a machine could outwit him - a distinguished military commander - in a game of strategy. Napoleon's formidable opponent, the world's first chess automaton, was billed as a soulless wooden mannequin encoded with masterly playing prowess. But the turbaned "Turk", as the machine became known from 1770 on, was not merely all whirring gears. It was an elaborate hoax engineered by Wolfgang von Kempelen. And concealed within the mechanical components was a highly skilled chess player and operator.
Machines are now widely known to have conquered the chess world, overmatching many of the finest grand masters. Although some may still reject the idea that artificially intelligent inventions can best humans at anything requiring imaginative thought, researchers in Abu Dhabi are busy teaching a computer some very human traits. The PAL group is now trying to code intuition, risk and style into Hydra, a 64-processor behemoth that is considered one of the strongest chess-playing entities ever. It can calculate 300 million positions in one second, according to its Germany-based programmer.
Chess - with its simple rules but infinite complexities - has for years served as an ideal prism through which scientists have measured the advancements of artificial intelligence. By comparison, the game of checkers is much simpler, having been "solved" last year by Canadian researchers analysing 500 billion billion scenarios over 20 years. "It is a very complex game because there's no solution to chess right now," said Muhammad Nasir Ali, Hydra's project developer since it began in 2003. "The number of possible moves and positions seems infinite."
Claude Shannon, the information theorist, calculated that there were more possible chess moves than there are atoms in the universe. That estimate has not daunted the Hydra program, which Mr Ali said was created as a "passion project" upon request by Sheikh Tahnoun bin Zayed al Nahyan. Hydra dominated the world computer chess scene in its early years, defeating the world's seventh-ranked grand master, Michael Adams, in 2005, and claiming the title as the top chess machine at the International Paderborn Computer Chess Championships the same year.
Unlike humans, the supercomputer also eliminates the chance of human error, said Abdul Mateeh Khan, the machine's programmer. "Usually in a game, there is room for human mistakes. With machines, this cannot happen," Mr Khan said. They "will just wait for a human mistake". As to whether Hydra has a distinct playing style, the German grand master Christopher Lutz's thumbprints may be embedded in the program's memory.
The machine is also known for chasing the enemy king relentlessly. "Yes, Hydra has a personality," Mr Ali said. "It can be very aggressive but it can also make some very enigmatic moves and sacrifices. Hydra is capable of placing traps. There are not many machines that can generate such a trap move." Mr Lutz, who is the team's main chess adviser, regularly plays against the latest versions of the program and reports weak positions to Chrilly Donninger, a German statistician and the chief programmer who writes the algorithms for Hydra.
To Mr Donninger, Mr Lutz is Hydra's "human sparring partner". While correcting a poor position is simple, an update can risk exposing Hydra to a new set of vulnerable positions. "It's like a medicine which cures flu but you get stomach cancer from it," he said. "Then one has to find another medicine without the stomach-cancer risk. Either I find a better solution or I come to a conclusion, 'It's better to have a flu than to die from cancer'. If one does this for many years, one gets a strong program."
Some chess machines are even built with a "contempt factor" to avoid draws. Describing his role in Hydra's development, Mr Donninger made clear his personal investment in its success: "I am the soul of the machine." Still, Mr Donninger is not convinced that machines can be taught intuition, as people in the artificial intelligence community believe. "It's definitely not possible," he wrote. "It's funny when grand masters interpret the moves of Hydra. They see very complicated plans and strategies. In fact, Hydra has no plans at all. It's just in the eye of the spectator."
This is because Hydra is based on a general set of principles ruled by Mr Donninger's mathematics training, which translate during a chess game as a set of patterns that may appear to exhibit human-like strategy. Frederic Friedel, the German co-founder of the computer chess software company ChessBase, believes it was an error for early chess programmers to try to devise a machine that emulated human playing styles.
"People thought the only way to play world-calibre chess was to teach it to play like a human being," he said. "This turned out to be completely, absolutely wrong. It doesn't work. The computer is sequential; the brain is parallel. They're doing something so different." Mr Friedel said he would challenge anyone watching a match pitting Hydra against a human grand master to distinguish which was which.
"'Good heavens', you might think, 'It's planning to pawn on my knight'," he said. "It saw that I can do this, so it's an intelligent entity." "But in my opinion, you have to call this intelligence even if it's doing something different. You can't just say it's a gigantic calculating machine, because that would be defining intelligence as only something that works like the human brain - which would make human beings the only intelligent things in the universe."
While humans may retain the edge on creativity, however, machines are also making their own mark in this realm. The computer known as Aaron, developed by the artist Harold Cohen, has drawn and painted stylised still lifes that can easily pass for human creations. Developed in 1973, the program is able to create the images through its own "imagination" and requires no human input. Perhaps just as fascinating, Mr Friedel said that ChessBase is developing an advanced version of a computer that can compose original music, applying the same AI principles used to create the best-selling chess program Fritz.
"We're developing a program that composes music and it works like Fritz," he said. While serious musicians have scoffed at the idea, saying that the tinny compositions from the early version of Ludwig sound like elevator music, Mr Friedel reminds them that this was the same attitude adopted by human grand masters early in the days before computer programs conquered human players. "Ludwig's position is exactly like Fritz, where the grand master said that's cute as hell, but of course I can thrash it," he said. "Well, just remember once we got to Fritz 11 and the world champions would say are you nuts? I'm not playing against it. In 10 years, Ludwig will be equal to any composer or arranger of music anywhere in the world. This will happen."