Deck building

Over time, a handful of excellent ressources have been created on the subject by the community:

Modules and density

Decks can be broken down in « modules »: group of cards with a similar objective. The percentage of cards each module contains is its density. As the normal hand size is seven, the expectation (ie. the number of cards of the module you can expect in any given hand) is the density time seven.

Spam modules have a density over 25% entail an expectation over 1.75: more often than not, two cards of the module in hand. This is a rare distribution, but necessary to continuously play a given card multiple times every turn.

Strong modules have a density between 14% and 25% and an expectation between 1 and 1.5: these cards will be used once or twice at each turn. Most decks have one or multiple strong modules, and their strategy can often be identified by checking them.

Standard modules have a density between 7% and 14% have an expectation between ½ and 1. They are supposed to be used regularly but not necessarily every turn. Strong and standard modules cards can be discarded when needed, as one can be confident to get another in hand quite soon.

Tactical modules have a density below 7% and typically provide specific support. From unique permanents and events to counters or responses to expected counters, they provide build-up power and security. As these cards are drawn sporadically, they are meant to be kept in hand for special cases or immediately discarded if the context is not favourable. In case they might come in handy, they should be kept in hand until needed: the sparse distribution of the module makes sure the cards will not jam the hand.

Master module

The Master module density depends on the rotation speed: one want to play one Master card per turn as much as possible, but not more. So the higher the rotation speed, the slimmer the master module density. Hence, the Master cards count stays stable across deck sizes: 12 to 15 Master cards plus, optionally, up to 6 or 7 Trifle.

Some decks can use specific cards like The Parthenon to get more Master actions and hence play more Master cards in the deck, though: this is the Multi Master Phase Actions (MMPA) strategy.

Rotation

Games usually last between 10 to 20 turns and decks are tailored with the peak card rotation speed in mind: the number of cards played on average between one unlock phase and the next, not counting the few first turns of build-up. The deck size should enable a peak rotation during 12 turns. The efficiency of a deck depends on its capacity to maintain an optimal rotation speed throughout the game: being stuck with no relevant card to play is a loosing situation.

Deck size examples

60 cards deck have a peak rotation of 5 cards maximum (5 × 12 = 60): in the mid-game it plays one master, three to four minion cards, and maybe a discard. This counts the whole turn, reactions included.

90 cards deck have a peak rotation of 7 to 8 cards (90 ∕ 12 = 7.5): in the mid-game it plays one master, up to a full hand of minion cards and maybe a discard.

Cycling cards and purposefully increasing the rotation to get more efficient cards is sometimes the only way to keep the rotation fluid. Multiple cards are available to provide good cycling options:

A card that is hard to play can jam the hand. Action modifiers, especially restricted stealth cards like Forgotten Labyrinth, can only be used when the opponent tries to block, so they can jam. On the other hand, action cards like Computer Hacking do not usually jam the hand as they can be played as soon as a minion is unlocked and ready to act. A tactical module for card rotation can be played in situations when jamming is expected.

Recursion

Even stronger than a good rotation, the recursion can be a strong point in a deck: it is the ability to fetch cards from the ash heap and get them back into hand. Only a few cards provide recursion:

Beyond its obious advantage of fetching just the right card at the right time, a good recursion allows a deck to adapt itself to the context and the table situation.

Building a deck in practice

1. Theme

The first step to build a deck is to choose a theme, a core principle to build upon. Multiple possibilities here:

2. Four strategic pillars

The second step, before adding more cards to the deck, is to define the four pillars of the deck strategy:

3. Cards

Now select the crypt and library cards to put in the deck. The minions you select will define the range of disciplines you can use and, symmetrically, the library cards you choose and their requirements will define what minions you want in your crypt.

During this card selection process, only add one copy of each card you want to play. Check the best cards and the deck archive for ideas. If you find tournament winning examples close to your deck list, they may give you ideas about what to include.

At the end you should have 4 to 12 crypt cards and 20 to 40 library cards. If you have more, it is time to sit back and ponder what is really useful and what should be cut. Consider your four strategic pillars to help you decide: payload is more important than delivery, itself more important than defense, and combat management comes last.

Note at this point you are working in single copies. This means that if you are building a rush combat deck, you should consider removing combat cards before removing a payload card like Fame. When adjusting the number of copies on the other hand, no pillar has priority and you may choose to use dozens of copies of the combat cards you kept in the selection and a single Fame.

Counters

If you can predict that specific archetypes will be a threat, consider including specific counters against them. From Fear of Mekhet against Inner Circles to Scourge of the Enochians against swarms, including Archon Investigation against greedy bleeders, there are a lot of options available and they can transform a losing position into a win.

If nothing specific comes in mind, consider the all-purpose counters of the game: Direct Intervention, Dark Influences, Sudden Reversal or Wash.

4. Card flow

Once the skeleton is ready, you can adjust the card flow. First adjust the crypt: use 4 (or more) copies for a star, 3 copies for an especially good minion if he is not mandatory for your play, 2 copies for an efficient one and 1 copy for support minions.

Then try to get an idea of the rotation speed: what would a normal turn be in the mid-game (including reactions)? How many minions are acting and reacting and how many cards are used? This will give you the target library size as well as the number of cards you need in each of your modules.

Finally, define modules and their density and adapt the number of copies in each of them to match the desired density, working module by module. Adjusting the master module first may be easier, as its density only depends on the number of master actions you expect to get. For the rest of the deck though, there is no predefined pattern: no strategic pillar has the priority in terms of density. A Stealth & Bleed can typically have two strong module for bleed and stealth, two standard modules for bounce and combat defense, and a tactical module against politics. A Wall deck, on the other hand, can have a spam module for wake & intercept, a standard module for bloat and only a tactical module for the payload.

This little calculator may help you figure out the number of copies you want to include for each card:

Probability to get a specific card = 0 %
Copies needed to get a draw = 0 copies

The probability to get a specific card is computed as the cumulated probability (sum) of having 1, 2, ..., n copies of the card.
The formula used is \(\sum_{i=1}^{\min\left(d,c\right)}\ \frac{\binom{c}{i}\binom{s-c}{d-i}}{\binom{s}{d}}\), with s: stack, d: draws and c: copies and \(\binom{n}{k}\) the binomial coefficients.
To second computation just computes the preceding probability for consecutive values of c.

Cycling

If one of your strong module can jam your hand (for example a strong stealth or a strong intercept module), consider adding cycling-oriented cards (cf. the Rotation section).

They should not be included blindly though; they can be an obstacle to a deck with no jam issue.

5. Test and refine

Once the first version of the deck list is ready, it should be tested to check if it behaves as expected. Just doing a dozen play simulations alone, playing out the first 3 to 5 turns with no opponents, can help you adapt the card flow a bit. If you have some time at hand, you can use the play test system devised by Paul Johnson to test your deck more thoroughly.

In the end, only real games can help refine a deck. Actual play get you accustomed to a deck strengths and weaknesses. It helps to note the cards cycled or discarded during a game: each card you do not use is a card you should consider removing.