Kaboom! - A Traveler’s Card Game
What is Kaboom!?
Kaboom! is a popular card game that is learned and played mostly among backpacking travelers. We learned it while trekking in the Everest region of Nepal and have since played our role in its migration to other travelers, hiking routes, and family holiday gatherings.
Because of its traveling nature, there are many many variations to both the name of the game and the rules. We have not found our exact set of rules anywhere on the interwebs, which is honestly very frustrating because we’ve now had to write them up ourselves.
The game of Kaboom! may also (and in some cases, more often) be known as Cabo, Caboo, Cabu, Cambio, Kabo, Kabul, Tamul, Hampi, Badouk, Babadouk… or other names. We learned it as Kaboom!, which is obviously the superior name because it is the most fun to say out of all the options at hand.
In addition to presenting the best name for the game, here we provide the BEST set of rules. As noted, you will find many rule variations, and we may be biased, but we think the rules below make the most sense and are the most fun. We will not confound the rules here by explaining other possible variations. Just stick to these rules and enjoy the game. You’re welcome!
Note that there is actually an official game called Cabo that has its own deck of cards for purchase. While we have not played this game, we’ve read enough to know that the rules are not the same as those of Kaboom! explained below.
The game of Kaboom! uses a standard deck of 52 cards WITH jokers (so actually 54 cards). Trust me when I say that playing with Jokers makes the game far more fun. You’ll see why as you start playing.
Without further ado, the rules of Kaboom!...
Basics
Type of Game
Kaboom! is essentially a game of memory, both of your own cards and potentially those of other players, with the overall goal of obtaining the lowest possible score.
Saying this is a memory game can initially scare people, but we have not found anyone that did not love this game once they started playing and got the hang of it.
There is also an element of strategy and the opportunity to view and swap the cards of other players in your attempt to best them, which most people tend to find quite fun.
What You’ll Need
Standard Deck of 52 Cards WITH jokers (so 54 cards)
Paper and pen/pencil for scoring
Number of Players
2-6 players
A minimum of two players are required to play, though adding at least one more player will make it more fun.
Ideal game play, where everyone is able to reach the draw/discard piles, slap the discard pile (an important component of the game), and reach the cards of the other players, would involve no more than six players. More than six players and things get a little too chaotic.
Four players is really the perfect number for game play in terms of both the memory component of the game and the ability to perform all of the actions listed above.
Game Setup
Each player starts with four cards placed face down in front of them, arranged in a 2x2 grid. No one may look at any cards.
The remainder of the cards are stacked into a single draw pile in the center of the table. Once the game begins, a discard pile will be created next to the draw pile.
If the draw pile is extinguished at any point during play, then pause the game, shuffle the discard pile, and start a new draw pile.
For fair game play, players should try to arrange themselves so that each player is about the same distance from the draw/discard piles.
Objective
Kaboom! is played as a set of 10* rounds that form a full game.
*Note that the number 10 is somewhat arbitrary. You can ultimately decide how many rounds you’d like to comprise your game, though it’s best to determine this before game play begins.
Throughout the game, player scores should be tallied at the end of each round and added to their score from the previous round. Keep an updated score for each player at the end of each round.
The best way to keep score is to create a grid with player names listed vertically along the left and the rounds listed horizontally across the top. Ta da!
The objective is to end the game with the lowest score. The player with the lowest total score at the end of all rounds is the winner.
Scoring for the individual rounds is detailed further in the ‘How to End & Score Each Round’ section below.
Card Values & Powers
A summary of card point values and the card powers/actions is found below. There are a few minor notes included, but the values and powers are discussed further in later sections.
Card Values
| Card | Value |
|---|---|
| Ace | 1 |
| 2 - 10 | Face Value |
| Jack | 12 |
| Queen | 15 |
| Red King | 0 |
| Black King | 30 |
| Joker | -1 |
Since this is a game where you are after the lowest score, you can quickly see which cards are no bueno and which cards are VERY NICE!
Card Powers:
Card powers are the powers (allowable actions) for cards that are drawn from the draw pile.
| If you draw ... | You can ... |
|---|---|
| 7 or 8 | Look at one of your own cards |
| 9 or 10 | Looks at one card of another player. Return the card to it's original position |
| Jack or Queen | Blind Swap. Swap any two cards on the table WITHOUT looking at them. |
| King | Visible Swap. Choose any two cards on the table. You may look at the cards and decide if you want to swap them. You must state to the rest of the table whether or not you are swapping the cards. |
Again, these powers/actions can only be used for cards taken directly from the draw pile. These powers/actions do not apply to cards taken from a player’s grid.
GAMEPLAY FOR EACH ROUND
While the goal of the full game of Kaboom! is to have the lowest score, the goal for each round is for your card total to be the closest to zero (in comparison to the card totals of each player). This is important to keep in mind as you progress through the round.
A score of 1 is better than a score of -2. But a score of -1 is equal to a score of 1. They are both one away from zero. A score of 0 is best, but does not guarantee a ‘win’ for the round. A score of 10+ may win a round if it is closest to zero among all the players. All of this is covered in the ‘How to End & Score Each Round’ section, but is good to have in mind as you read through the game play.
To begin each round, deal the cards so that each player has four cards placed face down in front of them in a 2x2 grid. No one may look at their cards yet. The remainder of the cards are placed in a draw pile in the center of players.
Each round consists of three main phases. The first is just a quick card ‘Peek’, the second ‘Slap’ phase gets the round moving, and the third phase is the bulk of play.
Phase 1: Peek
In the beginning of the round, all players will look at the bottom two cards in their grid (the ones closest to them) ONE time only. Try to remember your cards!
After this point in the game, players will only be able to look at their cards (or the cards of others) if they draw and use cards that allow this action (more on this later).
Phase 2: Slap
Once all players have looked at and returned their bottom two cards to their original face-down positions, game play begins with a ‘Slap Jack’-like phase.
Play begins with the person who had the score closest to zero in the previous round. If two or more people tied the round for closest to zero then the person with the lowest cumulative score starts (more on this later). If it is the first round of the game, simply pick someone to begin. Play will continue in a clockwise direction around the table.
To begin the slap phase, players take turns going around the table and quickly flipping the top card of the draw pile onto a discard pile.
If at any time a card is flipped that is the same number/face card as a card in a player’s grid, the player that has the matching card can slap the flipped card and discard the matching card from their grid onto the top of the discard pile.
For a card to “match” the card that is flipped, it simply has to be the same number or type of face card (Jack, Queen, King, Joker). Colors and suits do not matter.
The player that slapped and discarded their matching card now has one less card in their grid. This card is NOT replaced, the player simply has fewer cards. (Throughout the game, players may get rid of many, or even all, of their cards… or may even add some!)
Once a card has been slapped, the round moves on to the next phase. The player that slapped and discarded the matching card begins play for this third phase, which is the bulk of the game play for the round.
Uh oh… are you already confused? Did two people slap a card at the same time? Did a player accidentally slap a card that doesn’t match their own? Everything you need to know about slapping cards is covered in the ‘Rules for Slapping Cards’ section below.
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A Note on Flipping The Cards
When flipping cards directly from the draw pile to the discard pile (during the Slap phase of the round) or from your own face down cards onto the discard pile (more on this in the next section), players should flip the cards quickly and, to the extent possible, in a manner that allows equal card visibility to all players and does not give any specific advantage or disadvantage to other players, including themselves.
For example, always attempt to flip the cards up in a way that is not excessively blocking other players from seeing the card being flipped. Likewise, to the extent possible, you should not flip the cards in a manner that would give yourself an unfair advantage. Flipping cards from your own grid too slowly gives you an unfair advantage. Always make a quick flip.
Phase 3: Play
Once a player has slapped and discarded a card from the initial round of card flipping, Phase 3 of play begins.
The player that slapped and flipped up the matching card begins play by drawing a card from the draw pile and looking at it. The player should keep the card to themselves and not show other players.
The player has three options for what they can do with this card:
1. Use the Card Power. If the card has a power/action associated with it, the player can use this power. If using the power, the player must first discard the card and then announce that they are using the power.
| If you draw ... | You can ... |
|---|---|
| 7 or 8 | Look at one of your own cards |
| 9 or 10 | Looks at one card of another player. Return the card to it's original position |
| Jack or Queen | Blind Swap. Swap any two cards on the table WITHOUT looking at them. |
| King | Visible Swap. Choose any two cards on the table. You may look at the cards and decide if you want to swap them. You must state to the rest of the table whether or not you are swapping the cards. |
A couple of additional notes:
Cards 2-6, Ace, and Joker have no special powers. See the remaining two options for what you can do with these cards.
You don’t have to play the power of a card if you don’t want to. You can take one of the other card actions listed below, including discarding the card without playing the power.
If you draw a card with a power and choose to keep it, placing the card in your grid, you may NOT use the power of the card. (This should be obvious because you would not want other players to know what card you are placing in your grid.) If using the card power, it must be discarded.
Blind and Visible Swaps can include any two cards on the table, including your own.
For a Visible Swap, you must choose and look at the two cards at the same time. I.e., you may not choose one card, look at it, and then pick the other card.
Cards that are discarded to use their power can still be slapped. More on this in the ‘Rules for Slapping Cards’ section.
Card play in this game moves quickly. If you discard a power card and don’t use its power/action, once the next person has begun their turn, you have lost your chance to use the power.
2. Replace a card in their grid. The player may replace a card from their grid with the card from the draw pile, discarding the card in the grid.
The player may NOT look at the card in their grid when they are replacing it, whether or not they know the identity of the card.
The card being replaced must be flipped up quickly into the discard pile to give everyone an equal chance to see it.
3. Discard the card. The player may elect to discard the card they drew with no further action, whether or not the card has a power.
Once the player has discarded their card and used any card power/action (if able/desired), their turn is over and play moves in a clockwise fashion to the next player.
Players also have an additional fourth option of play on their turn. This is to say “Kaboom!” and take no further action. No cards can be drawn if you are “Kabooming”. The act of Kabooming is covered in the ‘How to End & Score Each Round’ section.
Slapping Cards
While a player is taking their turn, the other players are not completely idle. Game play should move quickly, and all players should keep watch of the discarded cards.
While the initial round of card slapping is over, players can continue to slap discarded cards throughout the game. It does not have to be a player’s turn to slap a card, player’s can slap a discarded card at any point during game play.
The slapping component of the game is the reason it is important for players to (1) discard any power cards before announcing their intention to use them and (2) flip up any replaced cards from their hands quickly. This gives everyone at the table a fair playing field for card slapping.
Throughout the game, players also have the opportunity to learn the card identities of other player’s cards. This can be done using the card power of cards 9 & 10, through a Visible Swap, or even through a Blind Swap if one of your cards is involved. It’s important to pay attention to where cards are moving around the table. The more cards you know, the more options you have.
When slapping a discarded card, the player can produce a matching card (or cards) from anywhere on the table, either from their own grid or that of another player.
If players know where more than one matching card is on the table, whether the matches are in their own hand, with other players, or in a mix of these positions, players may flip and discard both/any matches for a single slap. The only limit to the number of matches that can be discarded with a single slap is the number of matches that exist. (I.e., in most cases, other than with Jokers, the maximum would be three matches).
If a player correctly flips a matching card from another player’s grid, the player that flipped the card can now give the other player one of their own cards. Neither of the players may look at this card during this exchange and the card must be placed in the same position the flipped card was removed from.
There are penalties for flipping up an unmatched card after a slap.
Everything mentioned above and more is covered in detail in the ‘Rules for Slapping Cards’ section below, which should be read thoroughly before game play.
Play continues in a clockwise fashion as player’s work to remove/replace their cards in an attempt to get a round score as close to zero as possible while hindering other players from doing the same. This continues until someone is ready to end the round. This is described further under ‘How to End & Score Each Round’.
RULES FOR SLAPPING CARDS
Slapping cards is an important part of game play. It is a way to remove cards from your own grid (lowering your total points/score) and, if you know the cards of others, can also be used to move your cards to the grid of another player.
The rules below apply to all card slapping situations throughout the game, including the initial phase of draw card flipping to get the round started and during all regular game play thereafter.
Cards Players Can Slap. There are only two instances in which a player can slap a card that has been put on the discard pile.
During the initial phase of draw card pile flipping to get the round started. A player can slap the discard if they have a matching card.
During regular play, after a player has drawn a card and makes their discard. This discard may be the same card that the player drew or it may come from their face down cards.
NOTE: that a slap does not affect whether someone can use the power of the discarded card. For example, if a person discards a drawn card to use the power, another player may immediately slap this card. The player that discarded the card may still use the card power/action. The person that slapped the card still flips up their matched card, adding it to the discard pile.
Cards Players Cannot Slap. Players may only slap original discards, as noted above. Players cannot slap:
The cards that are discarded as the result of a slap, whether or not the discarded card matches the original card slapped.
Ex: Say Player A draws a King and then discards it. Player B slaps the discarded King and then discards a King of their own. No player can slap this discard (which is already the result of a slap). Likewise, if Player B slaps the King and then accidently flips up an unmatching card (not a King), no player can slap this card, as it is still a discard that is the result of a slap.
Who Can Slap a Card.
Anyone at the table can slap a card if they have (or know that another player has) a matching card.
It does not need to be a player’s turn in order to slap a card.
A player may also slap their own discard as long as it is within the criteria for cards that can be slapped (Rule 1).
Ex: Say Player A draws an 8 from the draw pile and chooses to swap out one of the cards in her grid that she currently doesn’t know the identity of (keeping the 8 and getting rid of a card in her grid). She flips the grid card up on the discard pile and it also happens to be an 8. Player A can then slap that 8 and also discard the 8 that she drew from the draw pile.
When You Can Slap A Card.
You can slap a card anytime after it has been discarded and before the next player takes a draw card. Of course, the quicker the better.
It does not need to be a player’s turn in order to slap a card.
You Do Not Have to Slap. You do not have to slap (or attempt to slap) a card if you have/know a matching card. If and when you slap a card is part of your own game strategy.
When Two Players Slap the Same Card. If two players attempt to slap the center/discarded card at the same time, the person that slaps it first is the one that ‘wins’ the slap and gets to discard their matching card. It is typically obvious who has won the slap because that person’s hand is the one that is on the bottom. If it is not completely clear between the two players who have slapped, the other players at the table should come to a general consensus as to who has won the slap and gets to discard their card.
Slapping & Flipping an Unmatched Card = 2 Penalty Cards. If a player slaps a discarded card and proceeds to flip up an incorrect/unmatching card from their (or another player’s) cards, the player must take two penalty cards. The (unmatching) card that was flipped up remains on the discard pile and the player must take two new cards – kept face down – and add them to their grid of cards. The player may not look at these cards. They are included as part of normal game play.
Slapping but Not Flipping Up A Card (‘Changed Mind’) = 1 Penalty Card. If a player slaps a discarded card, but then changes their mind and decides to not flip up/discard a card, they must still take one penalty card. Typically this occurs because the player has either forgotten where the matching card is and doesn’t want to risk an incorrect guess or they realize the matching card is no longer on the table before they actually take the step of flipping up a card. The player is still penalized for the incorrect slap, however less severely since they did not flip up an incorrect/unmatching card. The player must take one penalty card from the draw pile, keeping it face down and adding it to their grid. They may not look at the card. It is now included as part of normal game play.
Players Can Flip More Than One Card on a Single Slap. If a player knows the location of more than one match for a card they have slapped, they may discard any/all matches that they wish. Some examples:
Ex: A 7 card is discarded and Player A has two 7s in their own grid. They may slap the 7 and discard both of their 7s.
Ex: A 10 card is discarded. Player A has a 10 in their own grid and also knows the location of a 10 in Player B’s grid. Player A can slap the discarded 10 and then discard both their own 10 and the 10 of Player B.
See the rules for discarding cards from other player’s grids below (Rule 10).
Slapping a Card to Flip/Discard the Card of Another Player. During the game, players have the opportunity to view cards of other players. This can be done using power cards 9 & 10 or during a Visible Swap. Blind Swaps may also result in player’s cards being moved to other player’s grids. This means that players may know the identity of any number of cards belonging to other players. If a player is the first to slap a card, they may produce the matching card from anywhere on the table.
After a slap:If a player correctly flips/discards a matching card from another player’s grid, they can then move a card from their own grid to this player’s grid. Neither of the players may look at this card during this exchange and the card must be placed in the same position the flipped card was removed from. The player that slapped the card now has one less card.
If a player incorrectly flips/discards a card from another player’s grid (i.e. they flip a card that does not match the slapped card), the rules for slapping an incorrect card are the same as those above (Rule 7). The player that flipped the incorrect card must take two penalty cards. The original owner of the card now simply has one less card.
Slapping a Card that is Not in the Discard Pile. Slapping any card other than that on the top of the discard pile means nothing and there is no penalty other than looking stupid. If you wish to discard a matching card, you must be the first to slap the discarded card on top of the discard pile.
HOW TO END AND SCORE EACH ROUND
While the goal for the full game (total score at the end of 10 rounds) is to have the lowest score, the goal of each round is for your card total to be CLOSEST TO ZERO among all the players.
So, for example, a score of 0 would beat a score of -1 for the round. A score of -2 (two Jokers!) and 2 would tie, each of these scores is 2 away from zero. Similarly, someone with a single Ace would tie someone with a single Joker.
Ending the Round
Once a player thinks they may have the score closest to zero, on their next turn they can say “Kaboom!” (Let’s remember there is an exclamation point in there, so use a little pep when you say it!) This is the only action that the player can take on their turn. They may not draw cards or continue play in any way after they have said “Kaboom!”
Once a player has said “Kaboom!”, play continues around the table, the other players each getting one last turn. The person who said “Kaboom!” does not get an additional turn. Note that once a player has Kaboomed:
Their game play is over. Their final card/cards are locked in and cannot be changed.
They may not make any further moves in the game, including slapping cards to get rid of their own card or other players cards.
No other players are allowed to touch, change, or look at the card/cards of the player that has Kaboomed. Again, their cards are ‘locked’ and untouchable.
Once play has continued around the table and is finished, each player flips up their cards and adds up their score.
Scoring
For each player that did NOT say Kaboom to end the round, their score for the round is equal to the total value of all of their remaining cards.
| Card | Value |
|---|---|
| Ace | 1 |
| 2 - 10 | Face Value |
| Jack | 12 |
| Queen | 15 |
| Red King | 0 |
| Black King | 30 |
| Joker | -1 |
Thus, if a player has three remaining cards that are a 5, 3, and a Joker, their total would be 7. If a player has two remaining cards that are an Ace and a Joker, their score for the round is 0.
For the player that said “Kaboom!” (the Kaboomer), there are some additional scoring rules. This player is awarded or penalized set point values depending on whether or not they were the closest to zero.
If the Kaboomer has the score that is closest to zero, they are awarded with -5 points plus the (-) point value of their scores distance from zero. (For example, a score of -2 and a score of 2 would both be 2 away from zero).
Ex: If the face value of the Kaboomer’s cards is 3, their total score for the round is -8.
If the Kaboomer does not have the score that is closest to zero, they are penalized with +10 points plus the (+) point value of their scores distance from zero.
Ex. If the face value of their cards is 3, their total score for the round is 13.
If the Kaboomer ties with one or more other players (equally close to zero as another player), this is considered the same as #2. The Kaboomer is penalized with +10 points plus the (+) point value of their scores distance from zero.
Ex. The Kaboomer has one Joker (-1) and another player has one Ace (1). These scores are equally close to zero. In this situation, the Kaboomer would get a round score of 11 points (10 penalty points + 1 point for being one away from zero). The other player (with the Ace) simply gets the total of the face value of their cards (in this case, a round score of 1).
There is no reward for a player that ‘beats’ the Kaboomer (has a closer score to zero or ties). Their score is simply the face value of their cards.
Tally the player scores on the score sheet and continue to the next round.
Auto Kaboom
By now, you may have realized that if you are card slapping your little heart out, it’s entirely possible there will come a time when you have no cards remaining. Now what happens?
Auto Kaboom.
If a player has no cards remaining when their turn comes, they are essentially forced to “Kaboom!”, which is referred to as an auto Kaboom. Since they have no cards, their score is 0. Beware! A score of zero can still ‘lose’ the round if someone else ties you with a score of 0.
Just like a regular Kaboom!, after the player has auto Kaboomed, each player (other than the Kaboomer) has one more turn. When play is over, the cards and scores for the round are tallied as described above.
Continuing Play
The player with the score closest to zero (whether or not they were the one that said “Kaboom”), is the ‘winner’ of the round and should start the play (card flipping) of the next round. If there was a tie for the winner of the round (two people equally close to zero), then between the tied players, the player with the lowest total score up until that point should begin the next round of play.
HOW TO WIN THE GAME
As noted in the ‘Objective’ section, the winner of the game is the player with the lowest score at the end of 10 rounds.
After each round, the scores for each player should be tallied according to the process described in the previous section and added to their total from the previous round.
At the completion of 10 rounds, the player with the lowest total score is the winner!
Have fun!