Pondering how to encode the crucial information in each of his planned 15 pictures, Williams eye fell on a rotating painting he called his orrery. Once he'd solved that one, Williams decided on a hiding place for his prize and began thinking about the paintings themselves. It had to be something very simple, but absolutely unique. I thought Ive got to devise a system that has never been used before, he told BBC Four. And he wanted to avoid anything that could be solved by simply setting a computer to work on it. The artist had never been a fan of crosswords or anagrams, and felt sure anything he could devise in that format would easily be cracked by expert puzzlers. It had to be something detailed enough to identify the burial spot with great precision, but cunning enough to present a real challenge. Relating the challenge of devising a structure for the Masquerade puzzle, he writes: Williams returned home, and set about devising a structure for the master puzzle itself. Journalist Paul Slade picked up the tale on his blog. This leads to the eventual appearance of the hare in a window cut into the picture.

Rotating the carousel also rotates the letters so that the birds beak points at different letters depending on where it stops. At the top of the frame a model of the song thrush leans over, its beak pointing to a single letter. The circular wooden frame surrounding the image carries a message: DANCE THREE RINGS THE SONG THRUSH SINGS ADD ONE A DAY TO ENSNARE THE HARE. The Orrery, as it is titled, is a hand-painted carousel that Williams created in 1975, depicting a series of intermingled figures rotating in a landscape around a central mechanism. Now Ewbanks Auctions of Surrey have sold another amazing artwork by Williams, revealing that it was this that inspired Williams in his creation of Masquerade as it provided the means he needed to created his code without giving an advantage to crossword fanatics and expert puzzlers. The nation became obsessed by the story and it took two Manchester teachers three years to solve the mystery, by which time the hare had been dug up from its hiding place in Ampthill Park, Bedfordshire, by someone who had secured inside knowledge of its whereabouts.

It was in 1979 that artist Kit Williams published Masquerade, a picture book that sparked a nationwide treasure hunt for a hidden jewelled 18-carat golden hare, whose whereabouts were concealed in a set of cryptic clues featured in pictures and text throughout the book. A unique artwork that provided the key to solving the celebrated riddle of the golden hare a national sensation in the late 1970s has sold at auction for 20 times its estimate at £17,000.

Golden hare masquerade