DEK BOVINOJ

To use your mathematical skills to get more cards than your opponents.

A normal deck of cards. If there are many players, it is recommended that you mix more than one deck.

All black cards in the deck count as "positive" (plus (+), times (×) etc.) and all red cards count as "negative" (minus (−), divided ( ÷) etc.).

Ace is one (1), two (2) is two (2), three (3) is three (3), etc. Jack is 11, queen is 12 and king is 13.

Black cards count as plus (eg 7 of clubs is +7) and red are minus (eg 7 of diamonds is −7) as default. This is stacked on top of each other. For example. 7 of clubs and 7 of spades is +14, and 7 of diamonds and 7 of hearts is −14.

The goal is to combine the cards so that you get the number ten (10).
For example. 8 + 4 − 2 = 10, or 15 ÷ 3 + 5 = 10.
You can play a single ten (10) as well.

You can combine cards precicely how you want, as long as the result is exactly ten (10). No rounding.

Jokers make "positive" and "negative" swap places with each other (red counts as black and vice versa). If you then play a new joker, it will be the other way around again (red becomes red and black becomes black again). You can do this for as long as there are jokers in the deck. The color of the jokers does not matter.

There are three levels in the game (but you can also invent your own):

1. You only use plus (+) and minus (−).
2. You use plus (+), minus (−), times (×) and divided (÷).
3. All mathematical formulas are used.

Shuffle the deck thoroughly. The pile of cards not yet used is called the farm.

Give each player three (3) cards each, except the one who starts, who gets five (5). You don't show your own cards to each other. The cards in your hand are called one's barn.

The person who starts places two (2) cards of choice in front of them for all to see. That pile is called the pasture.

Then the player says "moo!", which means that the player have finished its round and it's the next player's turn. You can never take back a "moo!" Be sure to remind a player who didn't say "moo!" to do so.
Note: starting with five (5) cards and laying down two (2) is only done once in the entire game.

The next player can choose to:

1. put one (1) of their own card in the pasture, if they cannot collect ten (10), and say "moo!". This is called to do a moo. Then they draw one (1) new card from the farmyard and it's the next player's turn. The placed card in the pasture can now be used by everyone (but only when it's one's own turn).
   
   
2. combine cards from the pasture and one's barn to add up to ten (10). Then you say "dek bovinoj!" (which means "ten cows!" in Esperanto), and the player get all the cards that together add up to ten (10). This is called making a dek bovinoj. The stack of cards that you get through dek bovinoj is called one's haystack.
   Then the player draw new cards from the farm so they have three (3) in their barn (one must always have three (3) cards in their barn at the end of one's turn). After that, it's the next player's turn. Saying "dek bovinoj!" signals, just like with "moo!", that one's turn is over. And just like with "moo!" you can never take back a "dek bovinoj."
   
   
3. combine some/all cards from the pasture to make a dek bovinoj, without using the own cards from one's barn.
   
   
4. place a joker. If you do that, all the card colors will be reversed according to the rules above. Then the same player must do a moo or a dek bovinoj according to the rules above. You can only place one (1) joker at a time.
   If you only have jokers, you have to place them one after another until your barn is empty and do a moo.

Each player may only do the above once (1) per round.

This is repeated until all the cards in the farm, everyone's barns and the pasture are used up, or cannot result in any more dek bovinoj. If one's barn is empty, you simply continue on to the next player. Then the players count how many cards they have in their haystacks.

The player with the most cards wins!

"Dek bovinoj!" – What you say when you have succeeded in getting the number 10 through a combination of cards. It also signals that one's turn is over.

"Moo!" – What you say when you put a card in the pasture because you could not make a dek bovinoj. It also signals that one's turn is over.

The farm – The pile of cards not yet used, which are not shown to the other players.

Barn – The cards one have in their hand, which are not shown to the other players.

The pasture – The cards created through a "moo!", that everyone can see.

Haystack – The cards you get through dek bovinoj. It doesn't matter if you show them or not.

A red and a black card with the same number (eg hearts queen and spades queen) cancel each other out (eg +12 and −12 become 0). Use that to your advantage!

Try to combine the cards to get as many cards as possible! It is better with e.g. 4 + 4 + 2 than 4 + 6.

Putting "negative" cards in the pasture is usually better than "positive" cards. That is, until someone gets a joker...

Adam, Sofia and Peter will play, and choose level 2. Adam starts and draws five cards.

Adam can put both of his spades together to make a dek bovinoj, but since he's starting, he can't until his next turn at the earliest. So he puts the 9 of diamonds and the 3 of hearts into the pasture and does a moo.

Now it's Sofia's turn. She looks at her barn.

Sofia is a little sour that there is a 3 of hearts in the pasture, because 12 (queen) − 3 = 9. "Couldn't it have been a 2 of hearts instead?" she thinks to herself. She looks at her joker, but chooses to save it. Instead, she places her 7 of hearts in the pasture, does a moo and draws another card from the farm.

Sofia doesn't notice that she could have use her joker and then combine the 7 of hearts and the 3 of hearts to make a dek bovinoj! (7 + 3 = 10).

Now there are three cards in the pasture.

It is now Peter's turn. He is really happy with the cards in his barn.

Peter points to his king of clubs and says:

– This is 13, right?

Then he points to 2 of clubs:

– 2 of clubs, that's 13 times 2. That's 26.

He points to 3 of spades.

– Plus 3, that becomes 29. Then I subtract 9 from the pasture. That's 20. Minus 3, it becomes 17. Minus 7 becomes 10. Dek bovinoj!

Wide-eyed, Adam and Sofia watch as Peter takes all the cards out of the pasture and puts them in his haystack. With Peter's own cards, there are a total of six cards. Peter draws three new cards from the farm.

Now it's Adam's turn again, and the game can continue...

The game was made by Johannes G. and Leo G., 2024.

The rules for this game are licensed under Creative Commons Attribution-ShareAlike 4.0 International (CC 🅭 BY- SA 4.0).

You are free to:

1. Share – Copy and redistribute the material in any medium or format for any purpose, even commercially.
2. Adapt – Remix, transform, and build upon the material for any purpose, even commercially.

The licensor cannot revoke these freedoms as long as you follow the license terms.

Under the following terms:

1. Attribution – You must give appropriate credit,* provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
2. ShareAlike – If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
3. No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.

* A correct attribution in this case is: that the game is created by Johannes G. (alternatively: Johano Ĝo) and Leo G. (alternatively: Leo Ĝo) in the year 2024. No other attributes are required.

For more information about the license terms, please visit the Creative Commons license page.