Possession is quite possibly the most hated card in the game. This article is divided into three segments: how to play Possession, how to counter Possession, and when to go for Possession.
How to play Possession
In building your own deck, there are a couple tactics you can use to maximize the effect of the Possession. Throne Room and King’s Court are absolutely incredible when paired with Possession; it is the only way to get multiple consecutive turns other than Outpost, and even Outpost only gives you a 3-card hand. Drawing the golden hand of KC + KC + Possession + Possession + Possession should basically guarantee you the win, since you have 9 turns in a row to either win on piles or build an insurmountable lead. In addition, multiple Possessed turns eliminates one of the primary counters to Possession, since you can safely play Duration cards and other cards that improve the draw deck.
Council Room also synergizes with Possession. Play your Council Rooms, giving your opponent a bigger hand, then Possess it. (As noted below, playing a Possessed Council Room is even better.) Vault works similarly, though a canny Opponent that smells a Possession coming might just discard his good cards. And Golem is a great way to keep playing Possession. Golem’s main weakness is that it discards so much of your own deck, but who cares when you’re hardly using it anyway?
Your own attacks tend to anti-synergize with Possession. Curse-giving attacks are always strong, of course, but it somewhat decreases the power of the average Possession turn. (And if your opponent buys them, they’re one of the strongest counters to your Possession.) Handsize reduction attacks are more mixed; usually you wouldn’t want to Militia your opponents and then Possess them, but if you do it consistently enough, you can start to scare your opponents into discarding good cards to the Militia. Spies and Scrying Pools can be useful: keep good stuff on your opponent’s deck if you plan to draw those cards while Possessing them.
When actually Possessing your opponent, you should have two goals in mind: getting the biggest benefit out of the Possessed turn, and crippling your opponent’s future turns. Accomplishing the first goal is relatively easy: play turns like normal, keeping in mind that trash-for-benefit cards are a godsend. Normally those cards are limited by a desire not to trash expensive cards. But under Possession, when you can trash without consequence, they become impossibly powerful. Apprentice Colonies to draw 11 cards! Remodel a Colony into another Colony for yourself! Salvage Colonies for +$11! Mine a Platinum into an extra Platinum for yourself! Note that cards that provide benefits to opponents are great as well; courteously allow yourself to draw an extra card from a Possessed Council Room, or discard some cards via the Vault.
Accomplishing the second goal (crippling your opponent’s future turns) is a little more tricky. Be on the lookout for cards that involve choices. Like Lookout, which can be used to rearrange the top of the Possessed player’s deck to be as terrible as possible. After you’re done with Treasuries and Alchemists, decline to return them to the top of the deck. Even better, if your opponent has built a card-drawing engine with Cellar, you can often manipulate his deck by discarding junk cards, then selectively triggering a reshuffle so his draw deck consists of nothing but junk, ensuring several crappy turns.
Also look for cards that can pseudo-trash. Ambassador and Masquerade are most powerful: return two Colonies to the supply with Ambassador and generously help yourself to one to boot. Island is great as well: maybe his Platinums feel like taking an extended tropical vacation.
How to counter Possession
The converse of the above advice suggests that in order to deal with Possession, you should construct a deck that can gain cards useful to yourself but not your opponent, and you should avoid cards that, if Possessed, will destroy your deck. So no Ambassador, no Masquerade, no Island. Try building Gardens, Vineyards, or Duchy/Duke decks, since your opponent may be unwilling to gain those cards if he is going for Colonies or Provinces.
Prosperity offers another full-fledged counter: VP chips are always earned by the Possessed players, not the Possessor. Therefore, a deck built around Monument/Goons/Bishop, not aiming for Provinces, has the benefit of not only denying him his Provinces, but also providing you with VP chips.
The most common way to counter Possession, though, is with unconditional attacks. Your Possessing opponent will be unwilling to play Sea Hags, Witches, and Saboteurs against himself. This is especially true with Golem, since your opponent will be hesitant to play your Golems for fear of hurting himself. Attacks that involve choices are less good: Possessed Swindlers are little more than a nuisance, and Possessed Minions will only help him.
Other cards involving choices are also much worse when you get Possessed. Treasuries and Alchemists won’t get returned to the top of your deck. Envoy becomes much better in the Possessor’s hands than your own, especially in 2-player games. Herbalist and Navigator (and Courtyard, to a lesser extent) become massive liabilities, essentially guaranteeing you will have junk on top of your deck after the Possession. Loan, which you might ordinarily decline to play in the late game, becomes every bit as bad as you always feared.
A special note on Stash: Stashes are particularly vulnerable to Possession because the Stash cards have identifably unique backs. Drawing several them in hand (possibly from a Chancellor/Stash combo) is just begging to be Possessed. In addition, if your opponent Possesses your deck on a reshuffle, your Stashes are going to the bottom of the deck.
Durations are tricky. They’re great to have in your hand when being Possessed, since your opponent will be unwilling to improve your future turns. At the same time, playing Durations on the previous turn telegraphs to your opponent that you have a good hand to be Possessed. (For instance, if my opponent was going for Tactician, I would simply Haven my Possession from one to hand to another until she plays Tactician to discard her hand. Then I’ll gladly take the 10-card Tactician hand for myself.) The one Duration that is completely unaffected by Possession is Outpost, since your Outpost turns are never going to be Possessed. EDIT: See comments for discussion on how Possession and Outpost interact.
Finally, try to predict when the Possession is coming. Sometimes you can tell for sure, like when your opponent played a Scout on the previous turn, or you played Cutpurse or Bureaucrat on this turn. Even when you can’t, you can usually have a pretty good guess. Have you not yet seen it on this reshuffle? Is your opponent cackling with delight and a particularly vicious glint in her eye? Maybe you should junk up your next turn. Play the Adventurer even though you already have $11 in hand; leave some Victory cards on your deck with the Spy; use Navigator to discard good cards coming up; move your Stashes elsewhere; don’t put your Alchemists/Treasuries back on the deck.
When to go for Possession
Possession is a ridiculously expensive card—consider that, all else being equal, if you had bought a Silver instead of a Potion, every turn you buy Possession you could have bought a Province instead. Add to that the negative effects of having drawn Potions instead of a Silvers, and there are many situations where the best counter to Possession is not to get a Possession.
In the absence of Colonies and/or other worthwhile Potion cards, then I’m unwilling to buy an early Potion just for Possession. But if my opponent builds a deck particularly vulnerable to Possession (e.g., Alchemist/Herbalist, or Ambassador), then in the mid-game I will sneak in a Potion to try to play a Possession right as his engine peaks.
If Colonies are present and/or the board seems to call for me to get Potions anyway, then I will look to get Possessions, partially as a counter against my opponent’s Possessions. Colony games make Duchy/Duke, Gardens, and Vineyards decks (the main counter to Possession) less viable. In addition, Throne Room and King’s Court are so incredibly strong with Possession that if I will be buying them anyway, then I will certainly go for Possession. But if my opponent starts to stock up on unconditional attacks or Victory cards, then I will shift to another strategy.
In summary, Possession is not quite a must-buy card. But more than any other card, its availability considerably warps the strategy of the board. You don’t have to buy Possession, but you do have to plan for its effect.
- Your Throne Rooms / King’s Courts
- Opponents’ Ambassadors and Masquerades
- Opponents’ trash-for-benefit cards (Salvager/Apprentice/Remodel/Mine, but not Bishop)
- Opponents’ Islands
- Opponents’ Stashes
- Opponents’ cards that involve choices (Envoy, Treasury, Alchemist), including attacks (Minion, Swindler)
- Opponents’ cards that affect the rest of their deck (Lookout, Pearl Diver, Navigator, Courtyard, Herbalist, Loan)
- Opponents’ cards that involve choices
- Both your opponents’ and your own Council Rooms
- Your Golems
- Opponents’ duration cards (so long as you avoid playing them during the Possession)
- Opponents’ unconditional attacks (Sea Hag, Witch, Militia, Saboteur, Possession), especially when coupled with Golem
- Opponents’ junk decks (Gardens, Vineyard, Duchy/Duke)
- Opponents’ VP-chip decks
- Opponents’ Outpost
- Possession itself is a good counter to Possession, especially in 2-player games