Puzzle that was cracked 'too early' costs inventor his house

The jigsaw was advertised as perhaps the most difficult puzzle of all time and it carried a reward of £1m for the first person who could solve it.

The jigsaw was advertised as perhaps the most difficult puzzle of all time and it carried a reward of £1m for the first person who could solve it.

Its creator, Christopher Monckton, was so convinced of the inherent difficulty that he confidently estimated nobody would crack it for at least three years. He should have shown more caution.

Last night Mr Monckton admitted he had been forced to offer for sale his 19th-century Scottish mansion after someone solved the Eternity puzzle in less than 18 months. The sale of the grade A-listed property will help to offset having to pay the prize money.

"We think there is a winner," said Mr Monckton, 48, a one-time policy adviser to the former prime minister Baroness Thatcher. "The scrutineers are checking the entries. Originally I thought it would take a little longer but we never knew it would be this big. There have been people all over the world trying the puzzle."

Eternity is like no other jigsaw puzzle. Conceived and perfected over a 14-year period, it consists of 209 pieces, of different shapes, that have to be joined to form a 12-sided shape. All the pieces are the same colour on each side and unlike most puzzles there is no pattern to follow.

Retailing at £29.99, the game has sold fantastically well, with hundreds of thousands of optimists trying to crack the Eternity puzzle. Within a month of its launch in June 1999 it accounted for 20 per cent of the British boardgame market, beating the previous bestseller, Trivial Pursuit.

"I said it could not be solved simply by using a computer," said Mr Monckton, who hit upon the idea while researching hydro-dynamics in the British Library. "That has proved to be the case. A computer cannot take short-cuts in the same way as the human mind."

Mr Monckton, brother of Rosa Monckton, who was a friend of the late Princess of Wales, estimated that three years of royalties would have provided ample for him to pay out half the £1m prize money. The other half would come from an insurance policy he took out.

But with an imminent pay-out, he has been forced to put his 67-room home, complete with 200 acres and the title Laird of Crimmongate, up for sale with the Edinburgh office of Frank Knight estate agents. The property, a neo-Classical granite house near Fraserburgh, has a price tag of about £1.5m. Because he is seriously ill, Mr Monckton says the banks will not provide him with a loan that would allow him to hang on to the property, which he and his wife, Juliet, restored.

Just who has won the prize remains unclear. Entrants were required to sketch out their solutions on a grid that came with the puzzle and send them to the scrutineers, Gaebel,Watkins and Taylor, by the end of September, an annual deadline that Mr Monckton expected would pass without too many alarms. An announcement from the scrutineers is expected shortly.

The game has attracted huge interest and there are a number of internet "chat rooms" dedicated to Eternity, with puzzlers swapping hints and theories on cracking it.

The following message, left in the past few days by "Guenter", is typical of many: "Suppose we remove n random pieces from the E-set and replace them by random copies of the remaining pieces, taking care of parity. How much harder/easier would that make E?"

Cynics might observe this premature payout is also wonderful publicity for Mr Monckton, who is currently working on Eternity 2, the follow-up puzzle that will have between 883 and 1,001 pieces forming a three-dimensional rhombic dodecahedron. This game will retail at closer to £50, although the prize money could be as much as £5m. It will be aimed particularly at the American market, where Eternity 1 did not sell.

"It is a marketing man's dream," Mr Monckton said. "Can you make me pay out again?"

Before he completes his design for Eternity 2, however, Mr Monckton intends to meet those people who solved Eternity 1. "I will be very interested to meet them," he said. "I will also be asking their advice so that we can make Eternity 2 hard enough."