The notes were available at some branches, while other branches carried the previous $10 note variety with two triangles. A few weeks ago, the $1000 note with one diamond was found in circulation.

Symbols printed on the reverse of the notes were introduced back in 2008 as a new security feature used for authentication purposes by MAS. Despite the lack of information, a different symbol was used for each batch of notes. Based on the observations from the serial number, the symbols may either represent the print run number or the year of printing. It is also understood that there may be other symbols used, including circles and stars.

Most denominations showed the same pattern in the sequence of symbols. The earliest batches of such notes contained no symbol. From 2008, banknotes were first imprinted with one square, followed by two squares, one triangle, two triangles and one diamond.

This variety still carries the signature of then Chairman of the Monetary Authority of Singapore, Goh Chok Tong. On 21 May 2011, Deputy Prime Minister Tharman Shanmugaratnam was appointed the new Chairman of the Monetary Authority of Singapore.

It carries the signature of Emeritus Senior Minister Goh Chok Tong, the previous Chairman of the Monetary Authority of Singapore, suggesting that the banknotes were printed before 21 May 2011. Future banknotes will be issued with the signature of MAS Chairman Deputy Prime Minister Tharman Shanmugaratnam.

The colour is more vivid on the 3AA series, as printing technology continues to improve. Such colour improvements were also observed on the latest $100 notes. On the reverse, different tints are used for the space below the arches. We compare it with an earlier variety of the $1000 note with two triangles (right).

Now, does the $1000 1AA series exist? If it does, is the symbol is a square dot (based on the pattern for other denominations)?

Scans by Mr Bin Hee Jum

In a recent auction by Mavin International on 23 July 2011, the Singapore $2 note with two triangles was revealed. However, this variety is only available as an uncut sheet of three. Each uncut sheet contains prefixes 4EQ/4FQ/4GQ or 4HK/4JK/4KK.

The banknote still bears the signature of the previous Chairman of MAS, Emeritus Senior Minister Goh Chok Tong, instead of the current Chairman, Deputy Prime Minister Tharman Shanmugaratnam. It suggests that the note was printed before the appointment date of 21 May 2011. Banknotes signed by the latter will be expected as early as January 2012.

Also, the Singapore $5 note with one square was available as an uncut sheet of three at the auction. These notes had a prefix of 3AA. The Monetary Authority of Singapore (MAS) has often made such uncut sheets available through auction only.

Scans by Vincent Tan

From top: Peru 5000 Intis (1988), Singapore 100 Dollars (2009), Malaysia 2 Ringgit (1996), South Korea 10000 Won (2007)

The most commonly used feature is random flecks which glow brightly under ultraviolet light. These flecks cannot be seen under ordinary light and are often incorporated on both sides of the note. In order to provide a greater contrast, such notes are often printed on security paper which does not reflect ultraviolet light. For example, the 5000 Intis (1988) note from Peru and the 2 Ringgit (1996) note from Malaysia are sprinkled generously with fluorescent green and blue flecks.

Fluorescent security features can be also incorporated with other features on the banknote. On the 100 Dollar (2009) note from Singapore, the latent image bearing the MAS logo fluoresces under ultraviolet light. However, this wavy-shaped feature was not adopted by the polymer banknotes to make way for the island-shaped security thread. A security thread on the right-hand edge of the 10000 Won (2007) note from Korea gives a slight glow when placed under ultraviolet light.

Fluorescent pigment can also be used to print detailed graphics on the banknotes. The denomination is printed vertically across the 5000 Intis note, while numerals are printed in the middle of the Singapore $100 note. For example, putting a £20 (2007) note under ultraviolet light reveals a bright red and green figure 20. The serial numbers and seal on Singapore banknotes are printed with fluorescent ink.

Sometimes, these fluorescent features can be seen without using an ultraviolet lamp. For example, the numerals in the middle of Singapore’s Portrait Series of banknotes are large enough to be seen using by holding it next to the window, by means of ultraviolet rays from sunlight.

Today, many countries make use of such security features to deter counterfeiting, given that it is less easy to reproduce these features using commercially available printers. Often, these features are found on most denominations of modern banknotes. Even the 100 Trillion Dollar (2009) note from Zimbabwe has slight traces of fluorescent fibres embedded on it. Fluorescent features are found on Bank of England’s £5, £10 and £20 notes, and they are likely to be used on the Series F £50 note, to be released in late 2011.

If you wish to explore the fluorescent features of banknotes, invest in an ultraviolet lamp. This lamp should ideally emit light at 365 nanometres, which is often termed ‘black light’. For a cheaper alternative, visit a novelty store and find pens which allow one to write invisible messages which are revealed under ‘magic’ light. Here, you can purchase one at Daiso for $2.

A new variety of the $10 Singapore banknote with two triangles on the reverse was spotted in early May 2011. The two triangles were similarly printed in red, beneath the word ‘Sports’ on the bottom left corner of the note. Currently, there are a total of five varieties for the $10 note – with no symbol, one square, two squares, one triangle and two triangles, making it the denomination with the largest number of varieties at the moment.

Another denomination which has two triangles printed on it is the $1000 note.

In late January this year, banks started issuing a new variety of the $2 Singapore banknote. This polymer note from the Portrait series comes with a triangle on the reverse was seen just two months after the $10 note with one triangle on the reverse surfaced. Now, there are a total of four varieties for the $2 note – with no symbol, one square, two squares and one triangle.

The first prefix for this variety would be 4AA and has a signature of MAS Chairman SM Goh Chok Tong on the obverse.

Due to the effect of hyperinflation in the country, the Reserve Bank of Zimbabwe had to print money in increasingly higher denominations. This was one of the worst hyperinflations in history, where prices doubled every 24.7 hours in the month of November 2008. The annual inflation was estimated at 6.5 x 10¹⁰⁸ per cent as of December 2008. In order to regain confidence in the economy, the South African rand and the US dollar became the main currencies used for trade from April 2009.

Earlier this year, a news article by the Associated Press (AP) claimed that an increasing number of visitors to Zimbabwe bought these banknotes from street vendors. Although this banknote was not the largest denomination in history, it is certainly worth keeping one, as a souvenir. After the First World War, the Weimar Republic of Germany issued a 100 trillion Mark note. In 1946, the Hungarian National Bank introduced the 100 quintillion (10²⁰) Pengo banknote into circulation, but the twenty zeroes were not printed out. In fact, a sextillion (10²¹) dollar note was printed but never issued.

In countries prone to hyperinflation, metallic coins are seldom minted. As the prices increase rapidly, these coins were commonly melted down for export due to its diminished face value. In fact, the Zimbabwean banknotes were gradually printed on paper of a lower quality as more zeroes were added.

On another note, three local banks in Singapore are rolling out new and crisp banknotes for the Chinese New Year from today onwards. They are OCBC, DBS and POSB. On Tuesday, new bundles of notes are available at OCBC, HSBC, Citibank and Standard Chartered Bank. Maybank will allow customers to exchange for new banknotes on Friday.

I have written the following in February 2008, a few weeks after the release of the new banknotes.

The new series of S$10 polymer notes were released in late January 2008, bearing the signature of the Chairman of the Monetary Authority of Singapore (MAS), Goh Chok Tong. This was a move after the success of introducing the first batch of 10 million polymer notes to determine the suitability of using such notes in Singapore.

On 30th April 2004, the MAS announced the introduction of a new $10 Polymer Portrait Note on 4 May 2004. The new polymer notes have a design similar to the paper version, with some additional features unique to polymer technology. This is to preserve the public familiarity of the notes, as well as to minimise any alterations to note handling machines. The Portrait Series was launched on 9 September 1999 to welcome the new millennium.

The serial numbers for the first edition of the $10 polymer note had prefixes from 0AA to 9AA, then from 0AB to 2AB. The prefix 9AA was supposed to be the last of the series, but the error rate was so high that it went on all the way to 2AB. Banknotes that were misprinted were not replaced by a ‘replacement note’. Instead, this note is removed from the stack automatically by the machine, thus accounting for the jumps in serial numbers in uncirculated stacks of banknotes.

The first edition of the note, signed by the former Chairman of the MAS, Deputy Prime Minister Lee Hsien Loong, has the same dimensions as its paper counterpart. The 2004 edition is printed by Note Printing Australia (NPA), which has also printed the commemorative $20 note released in 2007 to mark the 40th anniversary of the currency interchangeability agreement between Brunei Darussalam and Singapore.

A limited edition folder of 10,000 sets worldwide was issued with notes bearing the prefix ‘MAS’, with a limit of not more than two sets per customer. A special overprint commemorates this first note issue of the MAS.

To protect the interest of our currency, I have included some of the more notable differences between the 2004 polymer notes and 2008 polymer notes. Please note that the following are just my observations under close scrutiny, and was done back in February 2008. There are other minor differences which were found between the two batches of banknotes as well.

Perhaps, these variations, together with the mysterious symbols found on our banknotes, would spark some interest in note collecting.

A new variety of the Singapore $5 banknote is finally spotted, with one square dot on its reverse. The small brown symbol is printed beneath the word ‘Garden City’ on the bottom left corner. These symbols have been introduced on polymer and paper notes since 2007, as a new security feature used by the Monetary Authority of Singapore (MAS) to authenticate the notes.

Similar to the latest banknotes in general circulation, these polymer notes bear the signature of MAS Chairman SM Goh Chok Tong. Serial numbers for this variety are believed to start at 3AA. So far, I have sighted the following prefixes in circulation: 3AC, 3AD, 3AF, 3AH, 3AJ, 3AN. If you happen to see any other prefixes for this new variety, please leave a message in the comment box below or drop me an email.

Earlier today, a bank teller has informed me that she had seen a $1000 banknote with one triangle on its reverse, with its serial number starting with 2. If you happen to come across such a note, a scan of the note is greatly appreciated.

As described by the Monetary Authority of Singapore, ‘there may be other shapes, such as circles, stars or triangles’. So far, only the square, triangle and diamond shapes are observed in general circulation. Perhaps this would mean that it would take some time before another series of banknotes is launched. Nevertheless, these symbols certainly created a level of curiosity within collectors.

To date, only the $5 and $10000 denominations remain devoid of the mysterious symbols. The following table summarises the different varieties found for each denomination of Singapore’s banknotes.

The Portrait series of notes was introduced back in 1999. Three different signature varieties have been featured on this series over the past eleven years. They include BCCS Chairman Richard Hu from September 1999, MAS Chairman PM Lee Hsien Loong from May 2004 and MAS Chairman SM Goh Chok Tong from January 2008.