An homage to possibly my favorite card. This guide is targeted to players who are familiar with the game but might not be familiar with how best to use the Conspirator card, the power of which is not necessarily immediately obvious. No doubt the more experienced players here will be able to improve upon what I've written, but I think the basics are all here.
Building and Executing a Conspirator Engine
The simplicity of the Conspirator card belies its power. Basically you get +2 coins, and if you play it as your third or later action in a turn, you get +1 Card and +1 Action. Simple and seemingly meager, right? Played as one of the first two actions, it's a Silver that eats up an action. But that tiny little bonus you get when you play it as the third or later action means you can chain them together. A whole sequence of Conspirators can add up to a whole lot of money, with which you can buy green. Few Dominion cards are more aptly named: a single Conspirator doesn't do much on its own, but a bunch of them can become a dominating power.
The main concern with a Conspirator Engine is kicking it off. For this article, I will introduce a couple of terms: When I say "Starter," I'm referring to that first action you will play to activate your Conspirators. For lack of a better term, I'll call the second action the "Substarter." Once you've played a Starter and a Substarter, your Conspirators are free to run rampant.
One of the fun things about the Conspirator Engine is how abruptly it activates: you'll be slogging through terminal Conspirators and scraping to get 4 coins per turn and then, suddenly, you'll rip through your whole deck in a single turn!
Part 1: When the Conspirator Engine Will Work
Although the Conspirator engine is fun and powerful, it can't thrive in all environments. Before jumping on a Conspirator engine the next time the Conspirator card shows up in a kingdom, take a few moments to make sure the conditions are right. The following, I would argue, constitute the ideal conditions for a Conspirator Engine. This is not to say a Conspirator Engine can't work under any other circumstances, but if you know what the best conditions are, you'll know what obstacles you'll have to overcome in other situations.
The other thing to keep in mind is that these conditions only apply to the Conspirator Engine. If the conditions are all wrong, that doesn't mean you won't be able to make great use of one or more Conspirators as a supplement to another kind of engine. The occasional Conspirator can make a nice addition to a Laboratory engine, for instance, or a Village/Smithy engine. But to make a Conspirator Engine, you ideally want all of the following to be the case:
1. Conspirator. You kind of need Conspirator in the kingdom to build a Conspirator Engine.
2. Strong trashing. Because each Conspirator only lets you draw at most one card, you need to trim your deck as severely as you can. You ideally want to see Chapel in there. Single-card trashers aren't going to be fast enough. Avoid Forge, too: it may be a fast trasher, but you'll burn too much time building up enough money to afford it, at which point you'll then have extra money to have to get rid of, too. Shy away from Trading Post, too: its trashing power is good, but you don't want those Silvers.
If you don't have strong trashing, then you can substitute non-terminal sifting; that is, something that allows you to filter through the junk in your hand. These cards include Cellar, Warehouse, and Hunting Party.
3. Absence of cursing attacks. Cursing attacks will stop Conspirator chains dead. That goes for Ambassador, too.
4. A good Starter card. The best Starter cards are villages -- cards that give you +2 Actions and +1 Card. In the absence of villages, other +2 Action cards will also work. If there are no +2 Actions cards, you might still be able to make the engine work with simple non-terminals, but you'll have a tougher time of it. It also helps (though, again, is not necessary) if the Starter card costs less than 4, as that gives you something to buy on turns when you don't have 4 to spend on a Conspirator. More on Starter cards later.
5. Preferably, an absence of hand-size reduction attacks. This is a less critical than many of the other conditions here, but I'm mentioning it anyway, as I will discuss the impact of hand size on the engine later. But if the presence of, say, Militia, is the only less-than-ideal circumstance, your Conspirator Engine is probably okay.
6. Preferably, some source of +Buy. When your Conspirator Engine kicks in, it may very well bring in more money than you can spend on a single buy. So you want a source of +Buy if you can manage it, though this is not a strict requirement. More on this later.
7. Optionally, some source of virtual +Buy. By this I mean Talisman, Workshop, and Ironworks. These cards can all help you obtain Conspirators and many of the best Starter cards faster in the early game. They aren't necessary, but one, maybe two of these bought early can help you rev up your engine faster. Once your engine is rolling, though, you'll want to trash these.
If, after surveying a kingdom, you determine a Conspirator Engine is a good fit, it's time to build one.
Part 2: Building a Conspirator Engine
One of your first two buys should be the strongest trasher on the board. If you're going to use Talisman, Workshop, or Ironworks at all, make that your other buy. An early Silver will help you build your engine, but be very careful about buying money: money only clogs up a Conspirator Engine. Whatever money you buy early might have to be trashed later.
For the whole of the early game, be singleminded about obtaining Conspirators at every possible opportunity. I wouldn't worry about the Starter cards at first, even if you get to the point where every hand you draw comes up with clashing Conspirators. The low cost of Conspirator and most of the Starter cards mean that it doesn't matter so much if you're not producing very much money per turn early on.
Of course if there's a plain old vanilla Village on the table, and you fail to produce the 4 coins necessary for a Conspirator, that's the perfect time to buy that Village Starter instead. Starter cards that draw at least +1 Card cannot gum up a Conspirator Engine, so buy as many of these as you like. But if, for example, your Starter card costs 4 or more, you should probably just stick to buying Conspirators until the pile is gone or you have the majority of them by a good margin.
Once the Conspirators are taken care of, you should, if you have not been able to do so already, get some Starter cards and preferably also some +Buy cards. Ideally, these are the same thing: Worker's Village makes an outstanding Starter card, because of its +Buy.
Barring that, follow the general rule that cantrips (actions with at least +1 Card and +1 Action) will not harm your Conspirator Engine. So Market and Grand Market are both outstanding supplements to a Conspirator Engine. Woodcutter, on the other hand, is not a great source of +Buy.
Continue to trash away your Estates and treasure cards. Ideally, you won't have any treasure at all, though you'll be able to work around a single Silver or Gold, maybe two. Once the Conspirators are gone, you'll also want to trash away your Talisman, Workshop, or Ironworks, if you bought any of those.
Part 3: More About the Starter Card
As stated earlier, the best Starter card gives at least +1 Card and +2 Actions. Why +1 Card? Because they won't stop you dead if a Conspirator chain you've already activated draws into them. Why +2 Actions? Because they don't need any help to kick off a Conspirator chain. But wait! Don't you also need a Substarter?
Yes, but if your Starter gives +2 Actions, your Substarter can be anything -- a terminal action, for example, not that you want to clog up your deck with terminals. Frequently it will be a non-activated Conspirator. Consider a hand with a Native Village and four Conspirators. You play the Native Village first, play a non-activated Conspirator second, and then the remaining three Conspirators will all draw for you.
Although the ideal Starter card also draws, Festival makes a decent Starter card despite not drawing. Why? Two reasons: It provides +Buy, fulfilling that optional accessory of the engine, and it also provides +2 coins all by itself, meaning that you can earn the same amount of cash with one fewer Conspirator that you'd normally require. Even so, you want to be careful. Inasmuch as Festival helps kick off Conspirator chains, its lack of +Cards can stop them, too.
If you're attempting a Conspirator Engine without any +2 Actions cards, there should at least be plenty of ordinary +1 Action cards to help you get going. The difference with +1 Action Starter cards is that the Substarter must also be a +1 Action card. That means you need two such cards to kick off a Conspirator chain, and that's much more difficult to manage. Because of this, the more they draw, the better: Laboratories are among the best of this type of Starter, because they offer +2 Cards. Markets and Grand Markets only offer +1 Card, but they provide a source of +Buy in the bargain. Treasuries are nice because once you've got a couple, you can keep them coming back to your hand turn after turn as you're revving up. But the 5-coin price point of all four of these cards makes them difficult to get early enough in the process. Ideally you'd like to have cheaper Starter cards available, so you can make good use of early turns that don't generate enough coins to buy a Conspirator. Something as simple and lowly as Pearl Diver will suffice: anything that offers +1 Card and +1 Action will help activate your Conspirators without gumming up the engine once it's rolling.
Part 4: Supplementing Your Engine
If, by the time you've drained the Conspirators and loaded up on enough Starters that you can reliably activate a Conspirator chain with any hand you're likely to draw, it may well be time to buy up green cards. But if you have any time left to spare, you can make your engine more resilient to the influx of green if you spare some turns to buy good supplemental cards.
Good supplemental cards are anything that offers at least +1 Card, +1 Action, and something else worth having, such as money (Treasury, Peddler, Bazaar) or a buy (Worker's Village), or both (Market, Grand Market), or an extra card (Laboratory), or an attack (Spy). If you've already got the extra buys, Peddlers are prime targets here, because when your engine kicks in, Peddlers will cost $0 on virtually every hand you play thereafter, so you can suck them up with whatever extra Buys you happen to have.
In the absence of hand-size reduction attacks, Cellar and Warehouse are also good supplements in moderation. The reason is that although they take up a slot in your hand, the potential is that they'll free up other slots by replacing those incoming Provinces with more Conspirators. Certainly you can overdo these, but a small number can loosen your engine up and keeping it rolling.
Part 5: The Importance of Drawing
Since each Conspirator (and most Starter cards, too, like Village) only draws one card, a Conspirator Engine can't skip over green cards and other non-drawing cards the way, say, a Laboratory engine can. Any non-drawing cards -- including treasure cards, terminal sources of +Buy, your trasher, and non-drawing Starters like Festival and Native Village -- can potentially end a Conspirator chain.
Let's take a more specific look at how "tolerant" your Conspirator Engine will be of these cards.
Suppose you have a Conspirator (C) Engine with Village (V) cards as your Starters. Suppose you've trashed everything else with Chapel (Ch), but you've just started to accumulate Provinces (P). Let's say your hand and your deck look like this:
Hand: V C C P P
Deck: C P V C C Ch C P C
You play the Village first. That gives you +1 Card, which is a Conspirator. Now you have three Conspirators. You play one as the Substarter. Then you play the next one, which draws a Province. Now you have one left, which draws a Village. Playing the Village draws another Conspirator. Playing that Conspirator draws another Conspirator. Playing that Conspirator draws a Chapel, and you're done with your action phase.
For your buy phase, you now have 10 coins to spend.
But now let us suppose those Villages were Native Villages instead, but everything else were the same:
Hand: NV C C P P
Deck: C P NV C C Ch C P
For simplicity, let's say you always use the Native Villages to put the mat cards (of which there are none) into your hand. You play the Native Village first. Then you play a Conspirator as the Substarter. Then you play the last Conspirator in your hand, which draws another. That Conspirator pulls in a Province, and you're done.
For your buy phase, you now have 6 coins to spend.
The lesson, again, is that not only doesn't a non-drawing Starter help you pull more Conspirators into your hand, they grind the engine to a halt when they're drawn by already activated Conspirators, too. You can still make the engine work, but it's not going to be as smooth.
The math is quite simple: For every +1 Card action in your initial hand, you can skip one non-drawing card in your deck. This is why in the best Conspirator Engine all of the engine cards are drawing cards, leaving only the green cards (and the odd lingering trasher) to gum it up.
This is also why I said earlier that hand-size decreasing attacks can have a detrimental effect on your engine. Not always -- in the example above, getting attacked by Militia just means you discard those two Provinces. But Militia is still a threat in general, because the fewer +1 Card actions you start with in your hand, the fewer non-drawing cards in your deck you can skip over.
Conclusions
Because of the unique considerations and constraints of the Conspirator card, it can be one of the most fun to play. While other types of engines can be constructed from interchangeable parts (e.g., a Village/Rabble engine is not greatly different from a Bazaar/Smithy engine, which in turn functions roughly like a Walled Village/Council Room engine), the Conspirator Engine requires coordinating a unique set of components to get working. Doing that can be a whole lot of fun -- enjoy making it work for you!
Edits: Additional remarks added by the suggestion of shark_bait and chwhite.
