Throne Room variant
A Throne Room variant is any card that allows you to play a single copy of an Action card multiple times. The archetypal example is Throne Room from the base set, which plays an Action card twice. Throne Room variants can function as a type of village.
 List of cards
- Throne Room - double-plays an Action card
- King's Court - triple-plays an Action card
- Procession - double-plays an Action card, then upgrades it
- Disciple - double-plays an Action card, then gains a copy of it
- Royal Carriage - replays an Action card after-the-fact, can be saved until needed, and more than one can be used on the same card
- Crown - either double-plays an Action card or double-plays a Treasure
- Ghost - digs for an Action card and double-plays it on your next turn
- Citadel - replays the first Action card you play on your turn
- Scepter - replays an Action card after-the-fact during the Buy phase, more than one can be used on the same card
- Mastermind - triple-plays an Action card on your next turn
- Specialist - gives you a choice of replaying the Action card or gaining a copy of it; also works on Treasures
- Flagship - replays the next Action card you play after it
- Reckless - replays a specific Action or Treasure every time you play it, but returns it to the Supply after doing so
 Related Effects
- Royal Galley - plays the same Action card once now and once on your next turn
- Elder - a fringe case: if the Action card you play asks you to "choose one" of several options, Elder allows you to choose two, but it doesn't double other features of the card
- First Mate - doesn't let you pay the same Action card multiple times, but lets you play multiple copies of the same Action card.
- Prince - plays the same Action card every turn for the rest of the game
- Counterfeit, King's Cache, and Tiara can only replay Treasure cards. This is superficially similar to Throne Room variants that double-play Actions, and is subject to the same rules; but the implications are different because Action plays are limited and Treasure plays aren't.
When you use a Throne Room variant to play the same card multiple times, you fully resolve the card's instructions each time, one after another; you don't just double the card's abilities. For instance, using Throne Room on Warehouse makes you draw three cards, then discard three cards, then draw three more cards and discard three more cards; you don't draw six and then discard six. If you replay a card that gives a choice between multiple effects, such as Steward, you may choose the same or different effects each time you play it.
If playing a card sets up abilities that take effect later in the turn, or on a future turn, playing the card multiple times will allow those abilities to take effect twice as well. For instance, playing Scheme during your Action phase allows you to top-deck an Action card during your Clean-up phase; playing the same Scheme twice allows you to top-deck two Action cards.
Some cards' abilities may have no further effects if played multiple times. For instance, Militia makes opponents discard down to 3 cards in hand. If you play the Militia a second time due to Throne Room, under most circumstances your opponents already have only 3 cards in hand, so this clause has no further effect on them. This doesn't stop other abilities of the card from taking effect (such as the + from Militia), unless the card is worded in such a way to make one effect contingent on the other.
 Duration cards
Most Throne Room variants can be used on Duration cards and will stay in play until the Duration card is discarded. For example, if Gear is played twice via Throne Room and the player chooses to set aside cards with Gear on either or both of the plays, both Gear and therefore also Throne Room will stay in play until the end of the following turn, but if the player does not choose to set any cards aside with Gear on either play, the Gear will be discarded from play at the end of the turn it was played and therefore so will the Throne Room. If Throne Room is used on Hireling, which stays in play permanently, then the Throne Room will also stay in play permanently, and the player will receive +2 cards at the start of each turn. If a Throne Room variant is used to play another Throne Room variant twice and then play a Duration card each time, only the Throne Room variant that played the Duration card directly stays out; the first Throne Room variant does not.
 Cards that leave play
Throne Room variants are a special exception to the rule that a card can't be played if the stop-moving rule prevents it from entering the play area. If you use a Throne Room variant on a card that removes itself from the play area, such as Horse, the card still gets played a second time; it doesn't return to the play area, but its abilities still activate as usual. However, abilities that are contingent on the card moving itself somewhere else, such as those of Mining Village or Madman, can only activate once; the card has already moved to where it's going and doesn't move itself a second time.
(Certain specific Throne Room variants, such as Royal Carriage, are worded in such a way that they can't be used on cards that leave the play area; but the above applies in general to Throne Room variants that don't stipulate that.)
In the past there were a number of cards, such as Goons, Haggler, and Groundskeeper, that had "while in play" effects below the dividing line. These effects come not from playing the card, but from the card being in play. While this distinction is immaterial in most contexts, it affected how these cards interact with Throne Room variants. Even if a card is played multiple times via a Throne Room variant, there will still only be one copy of the card in play, so Throne Room variants will not double the "while in play" effects of those cards. This fact is generally no longer relevant, because most of the affected cards have been removed or have received errata that changes their effects to happen whenever the card is played.
 Throne Room's Village Effect
Throne Room and its variants function as villages. A Throne Room used to play an Action card is equivalent to having a second copy of that Action card plus a copy of the card Village, making Throne Room a cost-effective way to add villages to your deck. This effect of Throne Room, while one of its main strategic benefits, may be non-obvious upon first read of the card.
Throne Room functions as a village because playing an Action card twice with Throne Room only costs 1 total Action (for the initial Throne Room play), but the resulting effect is 2 plays of an Action card. Throne Room therefore covers the Action-cost of the second play of the card in the same way that playing a traditional village before playing a second copy of the Action card would.
- Hand A: Smithy, Merchant, Merchant
- Hand B: Smithy, Merchant, Merchant, Village
- Hand C: Smithy, Merchant, Throne Room
(Assume the remainder of the cards in the 5-card starting hand to be junk cards such as Copper)
A player might naturally assume that Hand C, with the Throne Room and one Merchant, is most similar to Hand A, with two Merchants. But playing out the hands will reveal that Hand C in fact functions equivalently to Hand B, the hand with two Merchants and a Village.
In playing out Hand A, you first play two Merchants. Because Merchant gives +1 Card and +1 Action, you will still have a 5-card hand and 1 Action to use after each Merchant play. Merchant left your hand, reducing its size by 1, but it drew a card to replace itself leaving hand-size unchanged. Likewise, Merchant cost an Action to play, but it gave +1 Action back, leaving your number of remaining Actions unchanged. Finally, you can play the Smithy. Smithy increases your hand-size from 5 to 7 (leaving the hand, but drawing 3 new cards), but Smithy also reduces your remaining Actions to 0, as it cost an Action to play. Any Action cards drawn with Smithy will be drawn dead as you lack the actions to play them.
In playing out Hand B, you again play two Merchants, leaving you with 5 cards and 1 Action. But before playing Smithy, you can first play a Village. Like Merchant, Village is draw-neutral, so your hand-size won't change from playing it. But Village gives +2 Actions, while only costing 1 Action, leaving you with 1 more Action than before. Now, with 5 cards and 2 Actions, you can play Smithy to draw up to 7 cards, but with 1 Action remaining, you will still be able to play any Action cards you draw and continue on with the turn.
In playing out Hand C, you play a Throne Room and then choose to play the Merchant twice. This effect is draw-neutral: two cards left your hand (Throne Room and Merchant), but you receive the +1 Card effect of Merchant twice, so the resulting hand-size is still 5 cards. The effect is not Action-neutral, however. You spent one Action on the Throne Room play but receive the +1 Action effect of Merchant twice, so you are left with 2 Actions. So after playing Throne Room on Merchant you are in the same position as in Hand B after playing 2 Merchants and a Village: with 5 cards and 2 Actions, you can now play the Smithy to draw further Action cards without running out of Actions prematurely.
It may seem from this example that Throne Room is only functioning as a village when it is used on a card that gives +Action, but Throne Room's village effect holds even when used on terminal Action cards, albeit less obviously. A player who uses Throne Room on a terminal gets two terminal Action card plays while only expending one action, so while the player's Action count never numerically goes up, Throne Room has saved one Action that otherwise would have been spent.
For a concrete example, consider a scenario where you have built an engine that has just enough draw and Actions to draw to the end of the deck each turn and play every Action card in it. The deck currently has one Remodel in it, but you want the ability to remodel two cards per turn while still drawing and playing your whole deck. What do you need to add? For starters, you'll need to buy a second Remodel, but that Remodel costs one card (since you need to draw it each turn) and one Action (since you need to play it). So you will also need to add one more draw and one more Action, e.g. by adding a Lab and a Village.
Alternatively, you could add a Throne Room rather than a second Remodel. Like Remodel, Throne Room is a non-drawing card that will still take up space in your deck, so you would still need to add one draw (e.g. Lab) to draw the extra card now in your deck. However, in this case, you will not need to add an extra Village. Whereas playing two Remodels requires spending two Actions (one for each Remodel), playing a Remodel twice with Throne Room only costs one Action for the initial Throne Room play which will then play the Remodel twice for you. So Lab + Throne Room is fulfilling the same function as Lab + Remodel + Village. Adding just a Throne Room to your deck gives not only a second play of Remodel but sneaks in a village effect as well.
For Throne Room variants that play a card thrice (King's Court and Mastermind), the village effect is magnified. A King's Court playing an action card is like two extra copies of the card plus two villages (and also one Lab, which will be explained below).
 Chaining Throne Rooms
The optimal play with multiple Throne Rooms in hand will usually to be to chain them together by using one Throne Room to play another Throne Room which can then play two cards twice, rather than using each Throne Room on an Action card separately. Either way, two non-Throne Room Action cards ultimately get doubled, but the benefit of the chained version is that it gives an additional village effect over and above the normal village effect of each Throne Room in isolation. 2 chained Throne Rooms function as +3 Actions, 3 chained Throne Rooms function as +5 Actions, 5 chained Throne Rooms function as +7 Actions, and so on.
One way to understand this relationship is to count the number of Throne Room plays in each case. If you play Throne Room on Remodel and then Throne Room on another Remodel, you've played Throne Room twice. If you play Throne Room on Throne Room and then with each of the two plays of the second Throne Room you play a Remodel, you've played Throne Room a total of three times: the first Throne Room was played once, and the second Throne Room was played twice. As each Throne Room play has a village effect, the chained version that plays Throne Room three times should function as +3 Actions, while the unchained version functions as only +2.
For a visualization, it can be helpful to imagine each chained Throne Room as branching off from the very first Throne Room that was played. Because you only need to expend an Action for the first Throne Room in the chain, a bigger chain that plays more Action cards is getting more Action card plays from a single Action spent. Two Throne Rooms chained together will ultimately result in four plays of non-Throne Room action cards while using up only one Action, a net of +3 Actions. Three chained Throne Rooms will play six cards for only one Action, a net of +5 Actions, and so on.
Some exceptions exist in which chaining Throne Rooms together is not the optimal play. If +Action is abundant enough that running out of Actions is not a worry (e.g. because of Champion or Academy), then there will be little reason to chain Throne Rooms together. In these cases, holding off on playing Throne Rooms to give oneself more choice over which Action card to use them on may be the better play.
 King's Court's Draw Effect
Most Throne Room variants do not function as draw cards. Throne Room can be used to play draw cards like Smithy additional times, but compared to simply having two copies of Smithy, a Throne Room plus a Smithy takes up the same amount of space in the deck (two cards) and draws the same amount (six cards total, four cards on net). Therefore, while Throne Room plus an Action card will save one Action relative to playing two copies of that Action card, it does no better or worse in terms of draw.
However, two Throne Room variants exist that do function as draw cards: King's Court and Mastermind. Because these cards each play an Action card three times rather than two, they function as +1 draw, on top of the amount of draw one would normally receive from the Action card being played by them.
The extra draw comes from the fact that King's Court takes up less space in one's hand than the cards it is replacing. A King's Court and a Lab together are worth one more draw than three Labs. Using King's Court on Lab draws six cards total, the same as playing three Labs, but the net effect is four cards of draw rather than three because it only takes two draw to get a King's Court and a Lab into one's hand rather than three. Playing a King's Court on a Lab from a five-card starting hand will increase one's hand size to nine, while playing three Labs from a five-card starting hand will only increase one's hand size to eight.
The draw effect is most notable when used with Cantrip cards. Cantrips on their own are draw-neutral—no matter how many cantrips one plays, one's hand size will not increase. However, playing a Cantrip card such as Harbinger with King's Court does function as draw. King's Court and Harbinger together draw three cards, despite taking up only two spaces in hand, so the result will be increasing one's hand size by one.
Because King's Court costsand only gives one draw, using it primarily for its draw is rare.
Throne Room and its variants are at their strongest in engine decks and rarely used in Big Money decks. A big money strategy won’t have much use for the village effect, and in a deck with many treasures and few actions the risk that Throne Room fails to line up with any other action at all will be high.
In engine decks, Throne Room variants tend to be among the best villages. They are highly cost-effective as they double as both a village and an extra copy of an action card, and in large quantities their chaining effect can be substantial.
Even in engines, opening with a Throne Room variant will rarely be strategic. As with other villages, the card is most useful once your deck already contains a high density of action cards and will likely go to waste in the early game. Throne Room variants are better acquired in the mid-game once a number of other action cards have been added.
Throne Room and its variants also offer a high degree of flexibility because they can be used on different action cards on different turns depending on what effect is most needed at the time. For example, you might buy a Throne Room for the purpose of using it on a payload card like Artisan but then on a turn with a weak starting hand choose to use Throne Room on Lab instead to ensure that the turn kicks off.
Throne Room variants’ flexibility also helps in maintaining a balance between the number of villages and terminal action cards in one’s deck. One can alternate between using the Throne Room on villages, cantrips, and terminal action cards depending on the number of villages and terminals in the deck. For instance, if on turn 5 your deck has a cantrip, a Throne Room, and a terminal action card, then you can use the Throne Room on the terminal to play it twice; if you add a second terminal to the deck, then on turn 6 you can use the Throne Room on the cantrip to ensure you have enough actions to play each terminal once.
Throne Room variants synergize with some one-shot cards that trash themselves or return themselves to the supply (e.g. Horse, Experiment, or Tragic Hero). These cards often give a strong but fleeting effect counter-balanced by the fact that you lose the card once it is used, but playing them via a Throne Room variant allows you to eke extra plays out of a single copy of the card.
This synergy does not hold for every one-shot card. Many (such as Mining Village, Wish, or the early version of Prince) use restrictive wording—generally with the words “if you did” or “to”—that prevent an ability from activating a second time by making it conditional on the card actually being trashed, returned to the Supply, or set aside. Throne Room anti-synergizes with these cards because playing the card a second time will have little or no effect.
Lastly, Throne Room variants also synergize poorly with cards whose main benefits come from below-the-line “while in play” abilities, such as Goons, Highway (prior version), or Haggler (prior version). Even if such cards are played twice only one copy of the card is in play, so Throne Room will fail to double the below-the-line effects.