Scrying Pool (SP) is a card that can let you draw a lot of actions at one time. YAY! It also can allow you to remove a junk card from the top of your deck. YAY! SP also allows you to spy the top card of your opponent's deck to either remove a good card or leave a bad one. YAY! Lastly, SP always gives a card and an action, so it can't "hurt" your deck. YAY! With all of the good SP has going for it, is it always a must buy? Far from it!
When NOT to buy Scrying PoolCase 1: Lack of plus actions or many cantripsBasically without a village (or King's Court!) of some type, Scrying Pool is useless. Why? Because it really doesn't matter how many smithies, witches, militias and goons you can get in your hand if you can only play one. If the board calls for lots of actions to be played, SP will be able to get those actions in to your hand, but that does not mean they can all get played. Also, many spammable actions helps to increase your action density quickly.
Case 2: Lack of (some) trashingYour deck starts out with 10 non-actions, plus the potion you have to pick up, so at a minimum you will have at least 11 cards that SP doesn't like (and usually more!). Without trashing any of them, that means for 1 of your top 2 cards to have a 75% chance of being an action (therefore drawing 2 cards), you need to have 11 actions in addition to the SP already in your hand. For a 50% chance, you need roughly 6 action cards in your deck. That means to have a 50% chance of this card being a lab, you need 11 actions in your deck. That is a slow build up!
Case 3: CursesThis is an obvious counter to SP because more junk means less action density. Basically for every curse added to your deck, you need to add that many extra actions to compensate. Needless to say, Mountebank is especially bad because those coppers might as well be an extra curse!
Case 4: Lack of virtual $Obviously if you want your deck to be mostly actions, you want to keep your treasure count to a minimum. But you still need to buy cards, so having a way to generate $ from action cards is HUGE for Scrying Pool. Without anyway to generate coins from actions, you have to add treasures which just further dilutes your action density.
Case 5: Lack of plus buyThis alone is not enough to avoid SP, but it should make you think twice. Why? First off, without an extra buy (or gain) you can only add one action to your deck per turn, which means building up to a good density of actions will be slow, especially when you want to get numerous SP's, so your potion turns pretty much are dedicated to that early. Secondly, a SP engine is often slower than the fastest other options, so you are likely to fall behind to a good opponent. With a plus buy, this isn't a problem because it is easy to get to 13 or 16. But without? It can be awfully difficult to make up the lost time.
Case 6: Very quick gamesI'm looking at you JoaT! The idea behind this being if your opponent is hitting their 4th province by turn 12, SP is just going to be too slow. So JoaT and Masquerade do not bode very well for the SP player.
With all of these out of the way, what should you look for? When should you buy a scrying pool?
When to buy Scrying PoolCase 1: Cheap CantripsScrying Pool basically adds 1 card to all actions, because you draw the actions up until the victory/treasure card, so it adds 1 to your hand size. This means that your Pearl Divers, Great Halls, and Spies all become Laboratories. The best ones here are Village (gives +action), Pawn (can give +Buy OR +$), Conspirator (gives +2$ and is trivial to activate) and Haven (can save extra SP's if you draw your whole deck) because they are cheap (easy to mass) and give a fringe benefit.
Case 2: Light TrashingI say light trashing, because with too quick of trashing you can probably draw your deck sooner without SP, so SP will probably lose if both players go chapel. However, with slower/lighter trashing, SP should be enhanced more than other strategies. Good options here are moneylender and spice merchant (getting rid of your starting coppers should be enough to quickly get through your whole deck), Salvager (although getting rid of your estates might not be enough, the +Buy is a good addition), and Trading Post (Turning your 10 starting cards into 5 silvers helps eliminate enough junk to cycle through your deck, but also gives you enough economy to buy things).
Case 3: Hand Size ReducersSP is a great counter to militia, goons, etc. because discarding the 2 cards will rarely hurt you if you have a SP in hand, as you will quickly be drawing through your whole deck. Additionally, because you will be cycling extremely quickly, you can play YOUR militia every turn and make your opponent play 3 card hands. Good trade off!
Case 4: Vault, Secret ChamberVault (or Secret Chamber) and SP are a great combination. Why? Assuming you have some +Actions/+Buy, the general strategies is to draw all of your actions with a Scrying Pool, discard them for $, and then play another SP to
redraw them all. This can be repeated a few times, and then your other actions can be played out like normal, leading to huge turns.
Case 5: Vineyards (and Fairgrounds)The things that make SP bad are it is often slow, it needs to avoid many treasure cards, and you have to buy a potion. If only a card existed that combined these to give VP to allow for comebacks...
Vineyards are Donald X.'s gifts to Scrying Pool players. The idea being you can fall behind, but because you will have so many actions, buying vineyards can easily be worth as much or more than provinces. If you can avoid provinces altogether, it will be very difficult for most strategies to buy all 8 of them. Fairgrounds deserve an honorable mention, because any time you have a potion cost card it is not too difficult to get them worth 6 VP, and they will almost always be worth 4 VP.
Case 6: ColoniesColonies mean two things good for SP players: more victory points available, and a longer game. This means that it will take longer for your opponent to get their strategy together, but it will only take a SP player maybe 1 or 2 turns longer for Colonies than Provinces.
Playing with Scrying PoolCase 1: Spying your deckIt's one thing to know when to buy SP, but it's another to know how to use it. For your deck, always keep an action on top, even if you don't plan to use it. Out of coppers but have a moneylender on top? Don't discard it, just draw it instead! Assuming you show a victory card, discard it. Those are the easy ones. Treasures are a little more difficult. Coppers should almost always be discarded, as your next card should be better. Silvers/Golds... you probably shouldn't have many of these in your deck, but if you think you ABSOLUTELY need the cash, keep it and buy the card you need. Potions, if it's early and you need more SP's keep it on top, otherwise discard it as it won't do you any good.
Case 2: Spying your opponent's deckObviously, your goal is to both skip a good card from your opponent's deck, and leave a bad one on top. But what is a bad card? Well, it depends what strategy they're doing. If they are doing a SP deck too, ask yourself if you would discard it from your own deck, and you should probably do the opposite. If they are going more of a Big money deck, try and guess what their average money density, and then get rid of it if is higher. A good synergy with Scrying Pool is cards (namely other attacks) that benefit from knowing what is on your opponent's deck. Have a Saboteur in hand? Keep flipping your opponents cards until a Province is on top. Have a Jester? Wait for a card that helps you (ie. a good action) and leave that on top OR put a victory card and give them a curse.
Case 3: How many Scrying Pools to buy?The easy answer to say would be "as many as possible" and you can't go wrong with getting more. However, there is an opportunity cost. With the help of Scheme, or other cards to make sure you start with a SP in hand, you probably are fine with only 2-3 of them. However, as you start greening, every additional SP limits the chance of your engine stalling. Plus because it has a relatively low cost of 2P, it is easy on province turns (assuming you have +Buy) to pick one up even late in the game.
Case 4: When to buy Victory CardsWith Scrying Pool, you are almost certain to fall behind a more traditional strategy early. Hopefully you will be able to set up your engine quickly so that this lead will only be ~2 provinces, but with +Buy, falling behind is not necessarily a big deal. But when should you jump into the greens? Well, with alternate victory cards you can wait a little longer as that gives you a bigger pool of points to choose from. The exceptions being Nobles, Great Hall, and Island, as they still count as actions so buying them early actively helps your deck as well as giving you a VP boost. But what if there are no alternate VP cards? The simple answer is there is no perfect time to green -- it depends on the board. But a rule of thumb can be
wait as long as you can. In general waiting to make your first green turn a double (or triple) province, is a good idea, but obviously if your opponent is going too quickly you might need to simply settle for a 1 province turn.
Case 5: Other Potion CardsObviously buying a Scrying Pool requires you having a potion in your deck, so other Potion cards that are either too weak or slow to buy a potion on their own now become an option. Possession can easily be played every turn, and the opportunity cost is much lower if you already have a potion in your deck. Vineyards (as mentioned above) don't require the potion buy - you already have it for the SP! Even the Transmute can be worth looking at, as without estate trashing turning your starting estates into golds can be a real boost to your economy. Apothecary can be good in lieu of good copper trashing, as it can clear off your none action cards while building your economy. Another Alchemy card that can be good with SP is Herbalist -- it provides a +Buy, and it lets you return your potion to your hand early to quickly get SP's. The Alchemy cards that don't work well with SP are Philosopher's Stone (no deck left!) and Familiar (curses!). Alchemist and Golem don't hurt SP, but might not be worth the buy if you can already draw your deck.
Example Game LogsHere I use Remodel (normally very slow) as the only trasher to start drawing my whole deck by about turn 15. I cash in for 4 provinces on turn 17, and the last 2 (and 2 duchies) on turn 18. Note how I turned my coppers to Herbalists, as they were easy to draw.
Here I use light trashing from Mint and Expand to counter Witch (and use SP to play my witch very often). Caravans are useful here to expand hand size to guarantee starting with a SP.
Here I have just enough time to come back from a fairly quick Vault/Tunnel engine. Using the SP, I am able to pull a bunch of bridges into my hand, and I can use village to play them all.
Here I have a board with Vineyards and Scrying Pool. With the addition of Wharf for +Buy (and more cards) and Remake for trashing, this board is tailor made for SP.
Here I use a DoubleJack strategy (with disappearing village) to beat a SP strategy on a fairly weak SP board. Although he makes a mistake ending the game, my VP lead is simply too big to come back from.
Here my opponent goes for SP, and I overwhelm him with Ambassador and Familiar (although, I probably should have picked up some SP's myself)
Here, I go for SP on a board with A) NO trashing (besides Jack, which doesn't really trash), B) NO cheap cantrips to load up on... in fact no cantrips at all, C) JoaT which leads to fast games, and D) NO villages. How do I dominate here? Using Throne room, which allows me 2 searches with my SP for actions, and allows me to get the +Actions to play my Goons (and later bridge).
Lastly,
here I go Duchy-Duke, and the SP player has no choice but to try and fight me. Needless to say, his deck clogs and I win easily.
Works with:Hand Size Reducers
Colonies
Vault
Conspirator, Peddler, and many other cheap actions
Light trashing (Moneylender, Trading Post, etc.)
Vineyards (And to a lesser extent, other VP sources)
Other Deck-Inspection Attacks (Especially Jester)
Outpost
Other Potion Cards
Conflicts with:Fast games (JoaT, Masq)
Few cheap actions to pick up
No +Buy/ +Actions
Cursers (especially Mountebank!)
(Note: Some game logs will be added once CR is back up. Also, any advice is greatly appreciated as this is my first article)