One of the Commonwealth's greatest coin rarities, the 1920 Kookaburra Square Halfpenny design type 1

The glamour of the year '1920'

The year '1920' is indeed a glamorous one for the industry for it hosts some of the rarest and most famous coins of the Australian numismatic industry, a stunning line-up that includes:

• Australia's rarest florin, the 1920 Star Florin.
• One of Australia's most valuable shillings, the 1920 Star Shilling.
• Australia's most valuable sovereign, the 1920 Sydney Mint Sovereign.
• The 'Crowned Head' 1920 Kookaburra Penny, the only square penny in the series to depict the monarch wearing a crown.
• This coin, the 1920 Kookaburra Square Halfpenny, the rarest halfpenny of the series and throughout history has always been known as one of the great Commonwealth coin rarities.

When the Kookaburra Square Penny and halfpennies were created, Australians were recovering from the war and determined to lessen the ties with Great Britain. The mood even filtered through to our coinage! The Government planned to introduce a square penny and halfpenny with our native bird on the reverse. And the monarch minus his crown on the obverse! Provocative and contentious but uniquely Australian.

Australia entered a modern age post World War I. For many Australians, it was a time for breaking out socially, of questioning and changing old values and behaviour and enjoying the good life. It was a time of great change. People forgot the old and embraced the new in an attempt to leave the hardship and struggles of the war behind them.

New technology was being created, like toasters and cars, things that today we take for granted. The fashion world was exploding, great changes were being embraced in styles of dress. Australians were identifying with their own culture, keen to lessen the emotional and cultural ties with Great Britain.

Creating a new, totally Australian coinage was a part of the deal which is why the Government floated the idea of the Kookaburra Penny and Halfpenny envisaging a coin that would be unique to Australia.

The Government's plan was to discard the British-styled penny and halfpenny and to create a coin with a typically Australian design featuring the nation's native bird, the kookaburra. To maximise impact, a new shape was planned with the move from circular to square. And bronze was to be discarded and a new metal taken up, that of cupro-nickel.

Tests began at the Melbourne Mint in 1919 and continued for three years, ending in 1921.

Today there are approximately 200 kookaburra coins held by private collectors, making it on a par for rarity with the 1813 Holey Dollar, the nation's first silver coin. And the 1852 Adelaide Pound, the nation's first gold coin.

The best thing for collectors is that the 200 kookaburra coins do not bear the same design. The Melbourne Mint tested thirteen different styles introducing enormous interest, personal choice and procurement challenges into the series, for some designs are far rarer than others.

Aside from the concept of adapting every vending machine to accommodate a new square shape, the impracticalities of the kookaburra coinage is demonstrated with the size of the halfpenny. The bird is sculpted and three dimensional. The fields stunning.

Even without the crown, this portrait of George V is commanding and regal. It could almost be a proof striking, the details and fields are so good.