Starter Guide

Thank you for your interest in BOS! In case you didn't see it on the home page, BOS is the first luckless trading card game. This means no shuffling your cards, no drawing cards, and no dice rolls or coin flips. There are many things about BOS that make it unique, even though the unique things will appear to be very similar to things from other trading card games. If you have played another trading card game before, it is a good idea to think of BOS as a completely new game, and not use any biases from other similar games while you read these rules.


You are a powerful sorcerer, going to battle against another sorcerer. To help you in the battle, you've recruited three wizards. These wizards have small magic abilities and the power to call upon powerful monsters from the afterlife. These monsters, called summons, once existed in our world. They have copies of themselves conjured from the grave to be placed under your command, and are used to go to battle against other summons and gain an advantage over your opponent. How those summons came to be, or how they perished, is a story for another time.

But you are far stronger at magic than a mere wizard. You can use magic abilities called spells, which you cast at the cost of vim, the mana source of the world. But your greatest strength comes in the form of a world-ending force: A boss. In order to call upon it, you will need to complete a ritual to them, which is done by playing cards. Bosses, like summons, are creatures that once existed, but have previously died. However, these monsters contain the power to destroy the world and everyone on it in an instant. You are powerful enough to call upon them.

By beginning a battle with another sorcerer, your power causes vim begins to shatter across the battlefield, leaving behind latent energy called ether. This energy, though it is fragile and temporary, has drastic effects on the battle and gets stronger the longer the battle lasts. It can be tapped into to reduce the amount of vim you need to pay for spells or abilities.

Starting Info

At the beginning of the game, you have one deck of 24 cards. It consists of 3 wizards, 10 summons, 10 spells, and 1 boss, all of which will share the same color (either red, yellow, or blue). When you begin the game, you will set up your cards in various spots. Your summons are stored in a face-down pile called the castle, and your spells are stored in a face-down pile called the spellbook. Both your castle and spellbook can be kept anywhere comfortable, as long as all players can see them. You will also need one more face-up pile for all the cards you are finished using in game, which called your graveyard.

You may look at your castle and spellbook at any time. However, your opponent does not have access, because they are not public knowledge. Be sure to keep them face-down while you aren't looking at them! Also, the cards your graveyard are public knowledge, so both you and your opponents may look at each other's graveyards at any time.

You begin the game with 30 life. Bring your opponent’s life down to 0 to win! You also begin the game with 1 vim, though at the start of your first turn, it will increase.


Every card shares the same layout, with 4 spots that are universal across all card types.

  1. The top of the card is the name of the card. Every card with the same name will have the same text on it.

  2. In the left circle, there is a symbol to represent the type of card, followed by text that tells you the type as well.

  3. In the right circle is the color stone, showing what color the card is.

  4. In the box at the bottom is the ability of the card. Abilities are used to manipulate the game in your favor, and can do just about anything.

Certain card types have extra spots for more information, which will be elaborated on later in the guide.

Forest Sage: Yellow Wizard

Essence of Nature: Yellow Summon

Pyro-Maniac: Red Boss

Perfect Infusion: Blue Spell

Battlefield Setup

Your wizards begin the game face-down on the play area, forming three columns with your opponent’s wizards. Your boss also starts face-down on the play area, to the left of where you will be eventually placing your summons.

Wand: Wizard position (starts face-down)

Summoning circle with hand: Summon position (not on the play area to start)

Evil horns: Boss position (starts face-down)

To paint a picture of how this looks, imagine it like this: The two innermost rows of cards, which include the summon and boss positions, is the battlefield. This is where the creatures you and your opponent play fight against each other. Behind your summons is your castle wall, followed by your wizards, who are up in the castle with you. Your wizards are casting their magic down onto the battlefield from up high in your castle.


The game is played by taking turns, switching back and forth between the players. Determine which player takes the first turn by playing rock-paper-scissors, with the winner deciding who goes first. Once you are ready, begin the game!

Turns are split up into 4 sections, called phases.

  1. The first phase is called the startup phase. During this phase, you ready all of your cards. This means you take any of your face-down wizards, or any cards you have on their sides, and turn them face-up and facing forward. You also double your vim.

For example, if it is the very first turn of the game, you will have 3 face-down wizards and 1 vim. After you ready your wizards and double your vim, you will have 3 face-up wizards and 2 vim. Then your startup phase ends, and you move on to the next phase.

  1. The second phase is the summoning phase. During this phase, take any number of your wizards and turn them face-down, then place summons from your castle directly in front of them. This is called summoning. Make sure you match the summoning condition of the summon you want to play, which is found at the top of the card’s ability box. Note that a face-down wizard loses its ability while it is face-down, but your wizards will turn face-up again during your next startup phase.

For example, (using Forest Sage and Essence of Nature pictured above), you can turn Forest Sage face-down to play Essence of Nature from your castle, since Essence of Nature's summoning condition is "Summon using Forest Sage." You could also use Forest Sage to play any summon from your castle that has the condition "Summon using any yellow wizard," since Forest Sage is a yellow wizard.

  1. The third, and most important phase, is the main phase. During this phase you can cast spells, attack, use abilities that would happen during the main phase, or summon your boss. Casting spells and attacking can be done as many times as you want, if you can pay the costs to do so. You can also do any of these actions in any order or combination you want.

    • To cast a spell, pick the spell you want to play from your spellbook, then pay its vim cost, which is found on the top-right of the spell. Then reveal the spell to your opponent and use its ability. After the ability is done, place it in your graveyard.

If the ability has the word enchant, you place the spell underneath a valid card (For example, a spell like Glistening Light). When the enchanted card is removed from the battlefield, place the spell in your graveyard. You can even enchant your opponent's cards! But when they are removed from the battlefield, the spell goes to your graveyard, not theirs.

You can also choose to use ether to reduce the cost of any vim you would pay. The first time you would spend vim during your main phase, you can choose to use ether. If you do choose to use ether, the amount you pay is reduced by your turn count. If you don't choose to use ether, it vanishes until your next main phase. You can use ether on both card abilities that cost vim to use or spells. But once you spend vim during your turn, the ether will vanish.

For example, if it is your third turn, and you want to spend 5 vim, and you have not spent other vim this turn, you can use ether to reduce the amount you need to pay to only 2.

    • To attack, first select one of your summons.

Then pay the cost to attack, called acting. By turning a card on its side, you spend its action. A card only has one action while facing forward, and when it turns on its side, it loses its action. In other words, a card on its side has already acted, and cannot act again until it returns to facing forward. This means that an acted summon cannot attack again, since the cost to attack is to act.

Then, select any other summon on the battlefield to attack. You can even select one of your own summons! Remember: A summon can attack any other summon on the battlefield, regardless of where the summons are located.

Finally, compare the strengths of the battlers, which is found on the bottom right of the summon. Strength is a number that represents both the "attack power" and "health points" of the summon. Both summons are dealt damage equal to the other’s strength, and will take damage up to the amount of strength they have. A summon cannot take more damage than its strength, since strength also represents its health points.

For example, when a summon with 500 strength battles a summon with 2 strength, the weaker summon is dealt 500 damage, and the stronger summon is dealt 2 damage. Both summons take 2 damage, with the stronger summon being left with 498 strength, and the weaker summon being left with 0 strength.

Finally, check if a summon's strength became 0. If a summon’s strength becomes 0, send it to the owner's graveyard.

    • You may also attack a player to lower their life. This is called a direct attack. To attack an opponent, the column of the summon you are attacking with must not have a summon in it. Act with the attacking summon, like normal, and then declare that you are direct attacking.

(You can ignore wizards when direct attacking. Think of them as being up in the castle with you, looking down on the battle occurring below them)

Your opponent, at this moment, may choose to defend the attack by taking a summon in an adjacent column and moving it over to block. (There is no cost to block, so this may be done even if the summon you want to block with is acted) If they choose to block, a normal battle happens. Otherwise, the opponent is dealt damage equal to the attacking summon’s strength.

Note that an opponent who has not started their first turn is treated like they haven't walked up to the battlefield yet. This means you do not have an opponent until they start their first turn, so you are unable to attack them directly and any ability that would effect them does not.

Also, you may attack yourself directly, if you feel like it.

As a review of attacking: A summon may attack any other summon, but in order to attack a player, it needs to be in an open column.

  • To summon your boss, look at its summoning condition. If that condition is met, you may turn your boss face-up during your main phase. They are treated exactly like summons and can do everything a normal summon can do, including declare attacks, get attacked, use abilities, etc.

However, because these summons have the special name "boss," they have some additional rules attached. (These rules can be visualized if you picture your boss as if it is covering your entire battlefield)

    • Bosses are not treated as summons in the case of abilities. If an ability says, “Deal 3 damage to a summon”, it will not work on a boss. Likewise, if an ability says, “Deal 3 damage to a boss”, it will not work on a summon.

    • Bosses can block direct attacks even if they aren’t in a column adjacent to the attack. However, when a boss blocks, it does not leave its current spot.

    • Bosses can only attack an opponent directly if they have no summons and have no face-up boss. In other words, if their battlefield is completely open.

4. Finally, the last phase is the ending phase. During this phase, nothing special occurs. Some abilities may occur during this phase. Next turn!


To properly read an ability, break it down into 4 sections. As an example, we’ll use the ability of Angel of Grace: “During your main phase, act: Gain 2 life.”

  1. The condition, which is always in italics. Abilities can only be used when the condition is met. If there is no condition, the ability is always active. The condition for Angel of Grace is “During your main phase”.

  2. The cost, which is always in bold. Abilities can be used as many times as you want, if you can pay the cost for them. If there is no cost, then there is no sacrifice that must be made to use it. The cost for Angel of Grace is “act”, which means it must turn on its side to use its ability.

Note again that if there is no cost for an ability, you do not need to act to use that ability.

  1. The optional/mandatory symbol, which is either a colon : or an arrow -> . If an ability has a colon, it is optional. If the condition is met, and the cost can be paid, the ability may be used. If the ability has an arrow, it is mandatory. If the condition is met, and the cost can be paid, the ability must be used. For Angel of Grace, there is a colon, which means the ability is optional.

  2. Finally, the ability itself, which is always normal text. This tells you what happens! In this case, the ability is “Gain 2 life.”

To put it all together, “During your main phase, act: Gain 2 life” is an optional ability that can be used during your main phase if you can turn Angel of Grace on its side. If you do, you gain 2 life!

If multiple abilities would occur at the same time, the player whose turn it is currently decides in what order the abilities happen, but they must make all mandatory abilities go first.


As a final note, ether can have an adverse effect on games that last too long, called decay.

At the end of your startup phase, if it is your 11th turn or later, calculate the value of your turn count minus 10, then decay that many times. For example, if it your 13th turn, you decay three times. To decay, halve your life and vim, rounding down.

This rule hardly occurs, because a typical game of BOS finishes with each player playing 3-6 turns. Decay is only meant to end extremely rare games that would normally end in a tie.

Competitive Rules

If you are planning to participate in BOS tournaments, or if you're looking for a more serious match, there are some additional rules that you'll need to follow.

When playing competitively, you may use an additional pile of 10 cards called your reserves. Inside your reserves, you can keep a total of 10 summons or spells of any combination. These cards are not used in the middle of a game, but instead are used to prepare for a game.

To play a competitive match of BOS, follow this flowchart:

  1. Greet your opponent and reveal your color to them.

  2. Play one game of rock-paper-scissors with them. The winner decides who goes first.

  3. Set up your battlefield. Remember to keep your boss, wizards, castle, and spellbook face-down so your opponent doesn't gain any information.

  4. Swap out cards from your castle or spellbook with cards from your reserves. You may swap as many as you want, including none. Remember that you should know what color your opponent is playing and who is going first before swaping cards from your reserves.

  5. Play a game of BOS!

  6. The loser of the game decides who goes first for the next game. They also have the option to change the positions of their wizards, while the player who won does not.

  7. Repeat steps 4-6 until the match winner is decided!

Thank you for playing BOS! For detailed rules and card-related questions, please use the detailed guide. Any questions you have relating to specific cards can be found on the Card List page.