02-013 Dayakattai

02-013
Dayakattai

After writing several posts on traditional playing card decks, I would like to talk about traditional dice. Similar to playing cards, different countries have their own design of dice. And the history of dice is much longer than that of playing cards.

The first traditional dice I would like to introduce is “Dayakattai”. Dayakattai is a pair of long cuboid dice. They are typically made of brass and have dots punched onto the long faces (1, 2, 3, 0).

Dayakattai

Dayakattai is a Tamil dice game played by 2 or 4 people. Although titled as a dice game, dayakattai is actually a board game. The game play involves rolling dice and moving of playing pieces around a board. But traditional dayakattai never sold together with a board. The board is the floor. People draw lines on the floor with a piece of chalk and start playing. And the playing pieces? Just get anything handy from your home.

It is not easy to find chalk nowadays. And drawing lines on the floor will only get your wife angry. So, use a piece of A3 paper instead.

Same as other traditional games, there are slight variations on dayakattai rules between different places. A page on Autodesk Instructables explains the common rule. But the English is quite broken and is not easy to follow. Read also the French version of Wikipedia page to get a full picture of the game.

General Information

Player	2 to 4
Playing Time	?
Age	?
Year Released	?
Designer	(Public Domain)
Publisher	Jayam Traditional
Family	Abstract Strategy, Dice, Race
Score	4.8 (Board Game Geek)

 

Specifications

Dice size	Long cuboid dice made by brass
# of dice	2
Faces	4
Details	The game contains 4 long cuboid dice made by brass but only 2 are needed for the game. It does not come with the board or playing pieces and no instructions.

The game play

Where to buy?

Amazon. 

Dayakattai is a public domain game. Anyone can make. Many local small manufacturers in India produce dayakattai and the price is very low. However, most of them do not ship worldwide or cannot take international payment. Do try your luck on Amazon as I saw some suppliers sell dayakattai occasionally. Brass is the traditional material. Try to get a set that is made by brass.

I got my dayakattai set from a friend. He is an Indian living in Hongkong. After our government has dropped the quarantine requirement on overseas travels, he went back to India to visit his parents. He has not been visiting them for 3 years because of the pandemic. He placed the order for me on amazon.in prior to his trip. Amazon.in does not take international payment and does not ship worldwide. So, the dayakattai was sent to his parents’ home and he paid by his Indian debit card. He brought the dayakattai back to me after his trip and I pay him cash.

Dayakattai set made by Jayam Traditional

The dayakattai set I got is rather no frills. There is not much of packing. It only comes in a small plastic bag with a label on top. The bag was even broken when the goods arrived. But the dayakattai are still in good shape. There are no instructions of the game but a leaflet saying thank you for supporting his small business.

It is always my pleasure for supporting small business. 

A bit of mathematics

Before finishing this post, I would like to talk about the probability on rolling dice.

Rolling a standard D6 dice will grant you 6 possible results, being 1, 2, 3, 4, 5 or 6. You do not need a PhD to figure this out. And the probability of getting any number should be evenly distributed, being 1/6 or 0.1667. (This is actually not the case and I will explain later.)

Rolling a pair of dayakattai will grant you 7 possible results, being 1, 2, 3, 4, 5, 6 or 12. But the probability of getting any number is not so straightforward. Below table shows the ideal probability on rolling each number.

Result	Combinations	Probability
1	0+1 or 1+0	2/16 or 0.1250
2	0+2, 2+0 or 1+1	3/16 or 0.1875
3	0+3, 3+0, 1+2 or 2+1	4/16 or 0.2500
4	1+3, 3+1 or 2+2	3/16 or 0.1875
5	2+3 or 3+2	2/16 or 0.1250
6	3+3	1/16 or 0.0833
12	0+0	1/16 or 0.0833

So in dayakattai, you got a higher chance to roll a 3 and less chances to roll a 6 or a 12.

However, a more detailed study will find out that the probability is not evenly distributed between different side. On standard D6 dice, the one-sixth probability only applies to precision casino dice. As on Western or Chinese dice, the pips will cause a small bias to the randomness. Casino dice have their pips drilled, then filled flush with a paint of the same density as the material used for the dice, such that the center of gravity of the dice is as close to the geometric center as possible.

The phenomenon is more significant on dayakattai. Just roll dayakattai a few times, you will find that there is a higher chance to get a 3 than getting a 0. The reason is because of the pips drilled on the dayakattai caused the side with 3 pips become much lighter than the others. So it is easier to roll a 3 than rolling any other numbers on dayakattai.

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