02-015 Casino Dice

02-015
Casino Dice

Casino Dice, also called Precision Casino Dice, are standard d6 “right-handed” dice made to be very accurate and fair. They have sharp edges and corners and are usually 19mm in size.

Casino Dice

Regular dice that are used for board games or other purposes are manufactured via the plastic injection molding process, often made of polymethyl methacrylate (PMMA). The pips or numbers on the die are a part of the mold. Since the number of pips on each side are different, the center of gravity of the dice is not exactly at the same spot of its geometric center. This affects the fairness in each rolling.

Casino dice are made through a special process that ensures their accuracy and fairness. The pips or numbers on the dice are drilled into the surface, then filled with a paint that has the same density as the plastic. This way, the dice have equal weight on all sides. The center of gravity of the dice would be as close to their geometric center as possible and do not favor any outcome.

Casino dice are machined from a hard plastic called cellulose acetate, which can withstand the impact of throwing and bouncing. They may have a polished or sand finish, making them transparent or translucent, respectively. Their sharp edges and corners make them roll better and prevent tampering. Casino dice are also subject to various security measures, such as serial numbers, cancellation marks, glow spots, key letter spots, and casino logos to prevent cheating or forgery.

As its names suggests, casino dice are used in casinos for games like craps. Being preciously made, casino dice are also more expensive than normal dice. Amazon is selling casino dice at a price of around USD 3 each. With less than 9 dollars, you can get 100 pieces of normal dice.

The set I got from Amazon costed me USD 19.76. It consists of 6 authentic, table-played 19mm dice from Nevada casinos. Same as playing cards, casino dice are also replaced regularly to prevent wear and tear. Old dice were cancelled and sold as souvenir. The dice have a circular cancellation mark on one of the surfaces. This helps dealers identify if any cancelled dice are brought into a game by a cheating player.

US$19.76 for a set of 6 table-played 19mm dice from Nevada casinos

My set of dice is in different colours and from different casinos including Binion’s (1951), Boulder Station (1994), Harrah’s Lake Tahoe (1955), Harveys Lake Tahoe (1944), Peppermill Reno (1971), and The D Las Vegas (1980). Some of the casinos are even older than me! Holding the dice on hand is like owning a part of American history. The set also came with a drawstring-closure, black velvet pouch for storage and safe keeping.

Brillant made casino dice with logo and cancellation mark,
though this casino has some not so brillant history

Casino dice are d6 dice which can be used to play any dice games. But since the dice are from casinos, why don’t we use them to play craps? It is the only casino game that allows gamblers to have physical contact of casino dice.

General Information

Player	1 to 16
Playing Time	20 to 60 mins
Age	10+
Year Released	1125
Designer	(Public Domain)
Publisher
Family	Betting and Bluffing
Score	5.0 (Board Game Geek)

Specifications

Dice size	19mm precision casino dice
# of dice	2
Faces	6
Details	Casino dice are d6 dice precisely made to be very accurate and fair. They have sharp edges and corners and are usually 19mm in size.  Casino dice come with different colours. They are normally transparent and bear the logo of the casino and a serial number to prevent forgery.

The game play

Where to buy?

Amazon.

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02-014 Cowrie Shell

02-014
Cowrie Shell

After talking about the traditional long dice from India, the dayakattai, the next traditional die that I would like to introduce is also from that area. The name is cowrie shell.

No, I was not mistaken. I am really talking about those little seashells you can find in most part of the world, especially in the Indian Ocean. I was also surprised when I found out that people are using cowrie shells as binary dice to play games and also for divination. 

Cowrie Shells

Why using cowrie shells as dice?

History of using cowrie shells as dice can be traced back to ancient India. Such as the traditional Indian board game Pachisi is originally played with cowrie shells. A player's pieces move around the board based upon a throw of six or seven cowrie shells, with the number of shells resting with the aperture upward indicating the number of spaces to move.

The reason of using cowrie shells as dice is probably because of their wide availability. Cowries are common sea shells that can be found easily in most part of India. Their texture is also a reason why they are chosen for game playing. Cowrie shells are tough and not easy to break. A set of cowrie shells can be used for years without wearing. Besides, they are also beautiful to look upon. 

How does it work?

Cowrie shells are used as binary dice for playing traditional Indian board games, such as Pachisi or Chowka bhara. They can also be used to replace the long dice for playing Dayakattai. To play games using cowries, several shells would be thrown simultaneously. The number of shells used in each game varies. Sometimes, it is 4. But normally, 6 or 7 shells will be used. For divination, more than 50 shells will be thrown in a single time.

How to count the value also varies between games. In Pachisi, when played with 6 shells, the number of space a player may move is calculated in this way: 

Cowries facing up	Value	Earns another turn?
0	25	Yes
1	10	Yes
2	2	No
3	3	No
4	4	No
5	5	No
6	6	Yes

When played with 7 shells, it is calculated as such: 

Cowries facing up	Value	Earns another turn?
0	7	Yes
1	10	Yes
2	2	No
3	3	No
4	4	No
5	25	Yes
6	35	Yes
7	14	Yes

However, cowrie shell is not only a component of a board game. The shells themselves can be played as a standalone dice game. The traditional Indian game “40 shells”

General Information

Player	2
Playing Time	30 mins
Age	6+
Year Released	?
Designer	(Public Domain)
Publisher	OrderIQ, God?
Family	Dexterity and coordination, Children’s Game
Score	4.5 (Board Game Geek)

Specifications

Dice size	Snakehead Cowrie Shells at around 1" long
# of dice	7
Faces	2
Details	My cowrie shells are components inside a Pachisi game set. Cowrie shells can be purchased alone.

The game play

Where to buy?

Etsy

I got my set of 7 cowrie shell dice from my Pachisi game set. The set was purchased from amazon.in. My Indian friend who lives in Hongkong bought it for me as amazon.in does not take foreign payment or ship overseas. The Pachisi set was sent to his parents’ home in India. He brought the game back to me after visiting his parents a few months ago.

If you do not have a connection in India, you can buy cowrie shells from Etsy. Several sellers are selling cowrie shells at a reasonable price at around 1 USD each, with free shipment. The shells that came with my Pachisi game set are snakehead cowries in a size at around 1 inch long. I believe these are the traditional shells that are played in Indian villages.

A bit of mathematics

Before finishing this post, I would like to talk about the fairness of using cowrie shells as dice. Cowrie shell is used as a binary dice here. So, what is the difference between throwing a cowrie shell and tossing a coin?

Apparently, one of the difference is their shapes. Cowrie shells are easier to pick up than coins. Using coins to play the “40 shell game” would be a nightmare.

However, the unique shape of cowrie shell also caused them to have a curved probability distribution rather than flat probability as for a coin. A rough study shows that the probability of getting a 0 on cowrie shell die is only around 30%. Depending on the shell, that can get as low as 18.65% and as high as 39.11%. The same study also shows that the larger the shell is, the less likely it is to roll 1. And even between shells of similar size, there is significant variation.

Does that make cowrie shell dice an unfair gaming device? I don’t think so. As long as every players are agreed on playing the game with cowrie shells, then it is still a fair game.

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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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