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 and any ability that would effect them does not.
Also, you may attack yourself, 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 player 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 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 Light: “During your main phase, act: Gain 2 life.”
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”.
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.
The optional/mandatory symbol, which is either a circle with a dot in it or a circle with an arrow in it. If an ability has a circle with a dot in it, it is optional. If the condition is met, and the cost can be paid, the ability may be used. If the ability has a circle with an arrow in it, 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 circle with a dot in it, which means the ability is optional.
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.
Thank you for playing BOS! These are all of the rules you need to get started. If you have any questions, please reach out to us in our Discord server.
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.
To determine who goes first, you play a bidding game with your opponent. Each player secretly chooses a non-negative number. Then, they reveal it at the same time. The player with the higher number goes first, and the player with the lower number gets Ether equal to the amount they bid. Ether is a backup vim source that stays with you the entire game, and can be spent as a replacement for vim. For example, if you want to play a spell that costs 4 vim and you have 2 ether, you can pay its cost with 4 vim, or 3 vim and 1 ether, or 2 vim and 2 ether. Ether does not double.
As an example of the bidding game, player 1 bids 4 and player 2 bids 7. Player 2 wins the bid and can determine who goes first, and player 1 gets 4 ether.
When building your deck, 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, which means you cannot put bosses or wizards in your reserves. These cards are not used in the middle of a game, but instead are used to prepare for a game. Remember, you can only have 3 copies of a card in your deck, so that means you cant have 2 copies of Giant Ent in your castle and 2 in your reserves. You would need to remove 1 copy of Giant Ent.
Best of 3 Match
To play a competitive match of BOS, follow this flowchart:
Greet your opponent and reveal your color to them.
Play the Ether bidding game to determine who goes first.
Set up your battlefield. Remember to keep your boss, wizards, castle, and spellbook face-down so your opponent doesn't gain any information.
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 swapping cards from your reserves.
Play a game of BOS!
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.
Repeat steps 4-6 until the match winner is decided!
There is a mechanic in the game to ensure a winner is declared every game, called decay.
At the end of your startup phase, if it is your 11th turn or later, then begin to decay. You decay once for each turn you've started after your 10th. 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.
Some tournaments may want their matches to run quickly to make sure the tournament ends at the correct time. If that is the case, the tournament organizer may provide timers to make sure players finish their matches. When a player runs out of time on their timer, they lose. The recommended setting is 20 minutes, with a 1 minute delay every turn. (This delay means that your timer doesn't start ticking down until you spend an entire minute during your turn)
When an opponent is taking an action during your turn, you may pause the timer until that action is completed. Some actions the opponent could take during your turn would include:
-Viewing your graveyard
-Reading one of your cards
-Asking for a judge
-Choosing whether or not to block a player attack
-Choosing whether or not to use an ability