 # Do you know how to identify dates on coins? Part 2

By rcintas on the

Today we continue with the second post of the series that will help you out to guess the date of coin. You can find the first part in here: Do you know how to identify dates on coins? Part 1 ### Solar

This is the calendar used in Afghanistan since 1919, there was a period of 3 years in which they went back to the lunar Islamic calendar, between 1347(AH) and 1350(AH), equivalent to the period between 1928 and 1931.

Also the calendar is used in Iran from 1925, although between 1976 and 1978 they used the solar one, which was based on the foundation of the Iranian monarchy, (solar monarchy calendar). This calendar has the same duration as the Gregorian one although its structure is different. It has six months with 31 days, followed by five months with 30 days and the last one with 29 or 30 days depending on if it is a leap year or not. So there is not a direct correlation by months with the Gregorian calendar.

In order to calculate to which year of the occidental calendar corresponds a year of the solar Islamic calendar, we only need to add to the latter 621. Taking always into account that, although both years have the same duration, they don’t start and end at the same time, so there would be an error of some months in the calculation.

Applied to a coin it would be:

• 1 -> ١
• 3 -> ٣
• 7 -> ٧
• 9 -> ٩

This way if we want to calculate the occidental year that correspond to the solar islamic year 1379 we need to make these calculation:

1.379 + 621 = 2.000

### Hebrew

The Hebrew calendar is based in a complex algorithm, that allows to predict exact dates of the exact new moon, as well as the year seasons, based in mathematical and astronomical calculus, managing without empirical observations from that moment.

The Hebrew calendar starts with the Genesis of the world, that happened, according to the Jewish tradition, the Sunday 7th of October, year 3760 a. C. This way the Gregorian year 2015 is equivalent to the Hebrew year of 5775, so in order to change a Hebrew year to the Gregorian calendar it is enough to subtract 3760. As well as with the rest of the calendars the correspondence is not full since both years do not start at the same moment, we will always have a few months error.

Another thing to take into account is that in the coins, several times they omit the character that refers to the millennium, therefore the year 5735 can appear as 735. Also, the date can appear written from right to left:

Let’s see how these dates appear in a coin: • 4 -> Dalet -> ד
• 50 -> Num -> נ
• 300 -> Shim -> ש
• 300 -> Taf -> ת

So we would have:

400 + 300 + 50 + 4 = 754
5754 - 3760 = 1994

The hebrew year 5754 corresponds to the gregorian 1994.

### Taiwanese

The dates on the coins from Taiwan are expressed in the “republic year”. It starts on 1911 with the foundation of the Republic of China. Although the continental China was occupied by the communist forces in 1949, the Taiwan island was not occupied, so the government of the Republic of China established there and continued with the use of the calendar.

In order figure out the date of the gregorian calendar that corresponds to taiwanese year, we need to sum to the obtained year, the start year of the Republic of CHina (1911).

When inserting the dates in the coins there are several rules:

• A first group of four characters indicate “Republic of China, age in which the calendar is based. (中華民國)
• A second group formed by one up to three characters (numbers) that indicate the year (ABC)
• In third position there is a character that indicates that is a date (年)

Until the beginnings of the XXI century, the dates of the coins are written from right to left. However currently it is usually written from left to right:

Right-Left: 年 CBA 國民華中 Left-Right: 中華民國 ABC 年

In terms of the date numeration there are different cases:

• There is only one number: This one corresponds to the year of the Taiwanese calendar.
年 A 國民華中 or 中華民國 A 年
• There are two numbers: In this case one of them is the one that indicates a ten or a hundred (there is one number that is 10, 100) and the other numbers operate with it summing or multiplying depending on its position:
• The character near the date is 10 or 100. Then you have to sum them up
年 [十,百 ] A 國民華中 or 中華民國 A [十,百 ] 年
date ⇒ 10 + A o 100 + A respectively
• The character near the republic is 10 o 100. Then you have to multiply them: 年A [十,百 ] 國民華中 or 中華民國 [十,百 ] A 年
date ⇒ 10 * A o 100 * A respectively
• There are three numbers: This is the case of the central number it is always a 10 or a 100, and what you have to do is to multiply the first one (situated near the characters of the “Republic of China”), by the central one and to the result sum the third one(the one situated near the character that indicated the date).
年C [十,百 ] A 國民華中 or中華民國 A [十,百 ] C 年
date ⇒ A * [10,100] + C

Practical example: • 3 -> Sän -> 三
• 10 -> Shí -> 十
• 6 -> Ilú -> 六

This coin belongs to the second case, in which there are more than one digit forming the date. So it corresponds with the first case (the second symbol counting from the date symbol is a 10) so it would be:

6*10 + 3 = 63
63 + 1911 = 1974

The Taiwanese year 63 corresponds to the Gregorian 1974.

Next week we will continue with the part three of this series!