Traditional clockmakers in Japan were every bit as attentive to detail and accuracy as their Western counterparts - after all their patrons could be samurai, who had little tolerance of error and the ability to make their displeasure very clear.

But the Japanese methods of measuring time differed substantially from the ways familiar to Westerners, and this is reflected in the functions of the clocks, of which one of the features is a gauge for an expandable hour - to be used during the summer.

The Japanese were baffled by the concepts of time brought by Christian missionaries, but Emperor Meiji finally decided to accept them over the traditional forms. "It is time for a change", he said.

Now, a selection of these clocks are coming up for sale as part of The John Read Collection of Fine Antique Japanese Timekeepers sale at Bonhams.

John Read OBE is the leading authority in the West on Japanese clocks and conversely the man who introduced Rolex to Japan. He brought this fascinating collection of timepieces back to England following his time living there are training watchmakers from 1954.

A rare and important lacquered shitan makura dokei circa 1760

"These are outstanding clocks of their time." he commented, "Over time the clocks evolved to suit the peculiarities of the Japanese timekeeping system. Nevertheless they remained an incredibly expensive and rare item.

"One clock would have cost the equivalent of 20 years wages for a normal person. On top of this, each was looked after by a man whose sole responsibility was the maintenance of the clock. It is little wonder the clocks were so expensive."

Bonhams' sale takes place in London on May 11.

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