Three years ago Anurat Khokasai handed over all of his Buddhist amulets in exchange for a single rare gold coin. He hadn't become an atheist - he was investing in Siamese history.

As well as being chief marketing and operating officer for Union Frozen Products Co Ltd, Anurat is a dedicated coin collector, and this particular prize he was seeking abroad had been born in Thailand. He wanted it to come home.

Acquiring the 1894 coin involved six months of negotiating online with a fellow numismatist in the US. It's one of only a surviving handful of its kind, it's in mint condition, and it's made of gold, rare even at the time it was created, when silver coins were the norm in King Chulalongkorn's Siam.

"If this coin were a living thing, it would have been crying about being away from home for so long," says Anurat. "I was delighted to be the one to bring it home."

He also collects printing equipment, lottery tickets, stamps and cigarette packaging, but it's in coins that he's outdone himself, amassing a big enough cache in 10 years that he now wants to share a generous part of it.

The online auction he's arranging for early in the new year will be the first of its kind boasting a complete set of coins, "bullet money" and other forms of currency dating back to the second century, more than 1,000 items in all.

Anurat found his hobby by chance. At Bangkok's Chatuchak Weekend Market he learned that foreign collectors were buying up old Siamese coins.

"These items," he says, "aren't just currency - they're our history."

The history lessons that the study of money offers can produce surprises. Anurat discovered just how deeply rooted gambling is in this country as he uncovered metal and porcelain cowries.

The pieces had been manufactured all the way from 1347 to 1907 specifically for use in gambling dens. It took the introduction of public lotteries to lure most people away from the gaming tables.

The set that Anurat is offering online is valued at Bt20 million. The antique experts at Eur Seri Collecting are assisting in the auction, and Pantawanich Co Ltd is hosting it.

Anurat didn't need to go this route - there are plenty of willing private buyers for his collection, and they would have paid him more than he's going to get from this venture.

But he wants the coins to be in a Thai museum. The targeted bidders are local financial institutions and any Thai organisation willing to guarantee that the coins will go to a museum. Private collectors will have to register for the auction and make the same promise.

The age of the coins ranges from the recent past back through the Thonburi and Sukhothai eras to the days of the Funan kingdom of the Mekong Delta, between the first and sixth centuries.

There are coins from the Dvaravati kingdom that between the sixth and 11th centuries embraced what would become Thailand, and from the Sumatra-based Srivijaya kingdom of the seventh to 13th centuries.

Most are commemorative pieces made of pure silver or gold. The weight of the items that interest collectors ranges from a gram to 10 kilograms.

Siamese first used coins during the reign of King Rama IV. Until then, cowrie shells were for a long time the common currency, to be replaced by bullet money - actually ring-shaped rather than bullet-shaped.

Other forms included the Northeast's bars of silver and the North's bracelet-like currency.

The clear highlight of Anurat's collection is a coin handmade in Rama IV's time. It's the only one in existence and it's flawless. It was among the first to bear the Siamese inscription "Krungthep", a safeguard against forgery.

Another rare piece is a coin model produced by a British company during the reign of Rama III. It was not minted because the King discovered that its elephant design had already been used in Ceylon, as Sri Lanka was then known.

The large bullet coin known as Chor Rampoey is special for its craftsmanship as well as its heft. Weighing 40 baht - 608 grams - it was forged of silver for Rama V's 28th birthday in 1880. Only 17 were struck, and it's believed that just six survive.

In these and other pieces is a story of which Thais can be proud, Anurat says. The country's currency only really came of age during Rama V's reign, as a way of expressing its independence. Siam's neighbours at the time all used coins bearing portraits of foreign kings and queens.

"I want to see that pride reflected in these collectible items as they're appreciated by millions of people in a public place," Anurat says, "not just by a private collector in his own home."

Sirinya Wattanasukchai

The Nation