News Shop
Events Chat

[Strategy] Opportunity costs in Codex

I’m coming to Codex from the point of view of someone whose primary experience with games of this type is Magic: the Gathering. As I wait for my deluxe set, I’ve only played a few matches of Bashing vs. Finesse from the free print+play a while back. That leaves me plenty of time to think about Codex but with a dearth of practical experience. I have two strategic questions that I hope someone else can shed some insight into.

Some key places where Codex differs from Magic, at least in regards to the question I have are:

  • Your card draws in Codex are dependent on your current hand state; in Magic, your ability to draw cards is independent of any board state (excepting potential effects of cards in play)
  • In Codex, you build your deck as you play, whereas in Magic, you build your complete deck before the game starts.
  • In Codex, your discard pile is automatically recycled into your deck repeatedly, whereas in Magic, this can only happen if you cause it to happen with some effect.
  • In Codex, gold carries over from turn to turn, but mana in Magic disappears after each turn.

So in a very broad sense, the questions I have are just…how do you adapt to these things?

But let me be more specific. I’m thinking of two main decision points in a game of Codex that are affected in a complex way by the way the systems I mentioned above interact. First, when you are deciding what card, or cards, in your hand to play, and second, when you’re choosing what cards to tech from your codex.

In picking what card to play from your hand, the decision in Magic is usually pretty straightforward. (Please don’t pile on me for oversimplifying here; I know that there is a lot more to consider. The considerations are different from in Codex, which is the point I’m making.) You want to spend as much of your mana as possible (it doesn’t carry over to the next turn) to make the play that affects the board state for you as positively as possible. If this means playing every card in your hand, then a lot of times that’s really the right play. Maybe you hold a card back just in case the opponent has some trick, but that’s a strategic decision you make around what your opponent is doing, not around the systems of the game itself.

By contrast, in Codex, you also have to consider what you could draw next turn. If you do more than 2 things from your hand (one of which is probably a worker, so in many cases you only get to do 1 board-state-affecting thing from your hand), then you are giving yourself a disadvantage for the next turn, and even with cascading effects into turns after that as you at some point need to intentionally not play something to get back up to a full hand size. Having 5 cards in hand over 4 cards gives you 25% more options per turn, which is a huge win.

In Magic, flooding the board with cheap guys early doesn’t necessarily affect your ability to keep up that pace. In Codex, doing that is a tradeoff where you’re sacrificing a lot of ability to add to your board in the next few turns. I’ve found this decision to be one of the hardest I’ve faced in the game so far: Do I play more stuff now for a board advantage immediately, or do I hold cards in hand for a potential advantage in the future to have the right option?

Kind of playing off that is my second question. When teching, at first I thought there was usually no reason to tech two different cards, except for things like Rambasa Twin or some legendaries. In Magic, you’re limited to 4 of a given card in your deck, and you go right up to 4 with all your bread and butter cards. When building a deck, you are picking a set of cards that help you win the game. If there’s a card that doesn’t help you win the game as much, then you wouldn’t want that, and would rather want one that helps you win the game more. When you’re deckbuilding, you figure out whichever card helps you win the game the most, and you take 4 of it (since that’s the limit). Then you move down the line and find the card that helps you win second-most, and take 4 of that too.

That is sound logic (even if I didn’t explain it very well), so applying that to Codex, if you look through your full codex and determine, “at this time, the card that will help me win most is Argonaut”, then why would you not grab both Argonauts to ensure that you get one as soon as possible?

Thinking about this more, however, Codex again has systems at play not in Magic. Firstly, the opportunity cost of playing a card vs. receiving future card draws is at play. If you draw both Argonauts in one hand, you likely won’t be able to play both. That makes one of them a dead card, and if you had teched, say, one Argonaut and one Undo instead, you would have an additional option in hand. Plus there’s some inherent synergy to having one unit and one spell, since the unit doesn’t cycle through the deck repeatedly if you keep it alive, allowing you to draw the spell more frequently for a bigger impact on the lasting game state. Here, again, the question is about consistency vs. versatility. Do I want to definitely draw the card that in general is most useful, or do I want to have a chance to draw a more niche card that is more useful in some circumstances but less useful in others? Is it generally more useful to tech two of the same card (the best card for the given situation), or to tech more different options to adapt better to the circumstance?

tl;dr, because I know that this is an absolutely gigantic wall of text:

  • What considerations should be made when determining whether to play a card you can afford to play vs. not play it and draw an extra card next turn?
  • When is it appropriate to tech two of one card vs. one each of two different cards?

I know there aren’t definitive answers to these questions, and your ability to figure out the answers to these questions on the fly is the thing that separates good from bad players, but I am interested to hear everyone’s thoughts on how you approach these situations.


I’ve played white vs purple with several friends. I’m not sure if this is true for the Codex, matchup, or beginners like me. For almost every match, after I noticed it, there is a tipping point where incremental advantage is finally large enough for you to go all in and win now or next turn. If you notice this tipping point and act tip soon, it can put you shoo behind that your opponent is able to push ahead and win.

So far as I can tell, it is a good idea to play as conservatively as you can get away with, until you can get away with sealing a win. Then, you go all in.

On your second point, I tech 2 different cards very often. I tech x and y one turn and then tech x and y again the next turn. Usually for a unit and a spell.


Yeah, sometimes you just want to play two specific cards in a cycle and don’t care about their order. A good example is teching stuff at the start of turn 2, because those will usually be the only teched cards in the second cycle.

The small deck size also means that consistency isn’t as important as in MTG and you can get away with having only a single copy of a card that just isn’t useful to play twice. Legendaries are a good example. It can also be a good idea to keep single copies of cards in your Codex for fetching effects (Circle of Life, Calamandra…).

And obviously, teching two Rambasa Twins defeat the whole point of the card. :wink:

1 Like

The decision of whether or not to worker factors in here as well. If you play 2 cards and skip your worker, you’ll still draw 5 cards for the next turn.

I usually base this off of how badly I need a specific card on the next turn. Because of the deck cycling, you know which cards are still left in your deck before the next reshuffle. So if there are 5 cards left in my draw deck and I really want a specific one on the next turn, I am less likely to go down a card.

Another situation is if you’re behind on the board against a more aggressive opponent, and whatever you play is likely to die. In that case I like to play 2 guys and put one in Technician, because I’ll get that card back anyway.

I think this just depends on your strategy. If you are playing very aggressively with Fire, then you want to do 2 Lobbers just to keep the pressure on. If you’re going with a more usual pace, so the order of what you get isn’t that important, then 1 of two different cards is fine and is good for flexibility.

1 Like

I completely forgot about this as well. The opportunity cost of skipping a worker is another caveat I didn’t even consider. I just assumed that, to keep playing stuff “on curve” (which isn’t actually a concept in Codex as far as I can tell as much as it is in Magic or Hearthstone), you would pretty much bend over backwards to make sure you worker every turn. Maybe I need to reconsider that as well.

I’m far from the best player here, but I think about any potential play in Codex as having 2 costs: a gold cost and a card cost. Gold cost is fairly straightforward. Card cost is just the net number of cards you have to spend to make the play, which is usually 1 card for something played from hand (unless it gives you a draw). Heroes start out at a cost advantage over units because they cost 0 cards (although they also carry a potential gold cost if your opponent kills them and gets free levels for their own hero).

The real cost of spending gold on something is that you can’t spend that gold on some other thing, usually this turn but sometimes in the future.

The real cost of spending a card on something is a) reducing your hand size and therefore how many options you have on subsequent turns and b) slowing down your draw cycling so it takes you longer to get to your teched cards, net of c) if the card sticks around on the board it shrinks your effective deck size and speeds up your cycling.

The relative size of gold cost and the card cost varies a lot depending on your codex, your strategy, and the state and stage of the game, and judging it is one of the key skills of Codex. Here are a few rules of thumb though:

  • As a default, you want to be able to draw up to 5 cards unless you have a good reason not to. This is especially true in the early game, because you have more techs in the future so your card cost is high.
  • Some aggressive strategies can go down on cards early, but usually to establish a strong board presence that they can leverage to get back to parity. Often this can be because the opponent has to go down on cards to respond. On a conceptual level, you can think about this as slowing down the progression of the game so that you stay longer at lower tech levels, where you might have an advantage.
  • A worker is trading a card and a gold on this turn for a gold on every subsequent turn, plus access to tech buildings and a smaller deck / faster effective cycle time. It’s a present vs. future tradeoff. For much of the game, there is still a lot of future left and the present turn isn’t super critical, so you pretty much always want to worker. The closer to the endgame, the less true this becomes.
  • Your hand size stays relatively constant throughout the game, but your gold increases as the game goes on and you accumulate more workers. As a result, in the early game, you tend to be more gold constrained than card constrained. In the later game, you tend to be more card constrained than gold constrained.

One useful frame for evaluating what plays to make is to look at the net resources you and your opponent spent to get to a certain board state. If it costs you more cards/gold to answer your opponents threats then it cost for your opponent to make them, you are falling behind. That doesn’t mean it’s necessarily wrong to play that answer (maybe not stopping the threat would be even worse), but you should be aware that you are going down on resources to do so.


Yet another thing that changes decisions from MtG is the inability to stash cards by default.

In MtG, not playing a card means that you’ll be able to play it on a later turn. Likewise, playing a card usually makes it unavailable for the remainder of the game.

In Codex on the other hand, not playing a card may make it unavailable for you for a couple turns, so you may want to play a useful card even if the stars aren’t 100% right. For example, you might want to play that board clear now even if you are sure you could bait your opponent into expanding his board even more.
Playing a card now can delay a repeated play even longer if it is a permanent because it might not return to your discard pile before the next shuffle, but generally playing it has little effect on replayability.


To be fair, the situations where I would actually skip a worker are very, very rare. I’ll do it in situations where I’ll lose if I don’t, or trying to set up a lethal play for the next turn.

1 Like

I think the long answers to both of these in Codex are almost always “it depends on a lot of factors and each situation is fairly unique”, those factors of uniqueness being the matchup, the current turn, the current board state, your current deck cycling state & gold (aka econ state) etc.

I’ll try to boil down basic heuristics I’ve used when starting out to answer each individually though:

###What considerations should be made when determining whether to play a card you can afford to play vs. not play it and draw an extra card next turn?

Usually this boils down to “if I play an extra card/two NOW, what is the risk I get that board advantage erased, and what are the chances it leads to a big play this turn or next turn?”

Things to consider when wondering “risk of getting wiped” are:

  • How much haste / direct damage / direct removal spells does my opponent have access to
  • How likely were they to tech those cards, given the events of the game to this point
  • How likely are they to have those cards in hand, given their current cycling state

For example:

  • playing against Anarchy, Zane could come out and bring sharks, that’s 8 hasty damage across 3 attackers for 7 gold.
  • Strength tech 2 could drop Degrey and erase all tokens, dangerous against a Feral frog rush or Necro skeleton army.
  • Law could bring Bigby + Judgement day to totally wipe tech 2 units and below.
  • Necro + black starter has Doom Grasp for your big baddy, sacrifice the weak for your lowest thing, deteriorate to finish anything on 1 health…

You get the idea

To answer “will this make a big play this or next turn”, ask yourself:

  • Can I take away what I’ve determined is my opponent’s “primary win condition” (a maxed out hero, a strong tech 2 deck, a tech 3 unit, etc)
  • Can I set my opponent significantly back on board position that will lead me to locking them out of their primary win condition (killing a tech 1 when their hand is likely to have one, take a hero away when their hand is likely to have a key spell)
  • Can I put enough damage on base that I finish it or leave it very near finishing, and will I win a race to finish it (this only applies to certain decks, primarily decks with any Red, Demonz, Peace, or Bashing, that have strong access to direct base damage)

When is it appropriate to tech two of one card vs. one each of two different cards?

This is more about “reading the opponent”. If you are very certain of your deck’s win condition and what your opponent is doing, and you’ll be cycling soon that you want the best possible draw odds, it is absolutely appropriate to tech 2x of the same card.

One thing you’ll find about codex that’s different from magic though: your opponent has many reasonable options, you’re often unsure what they’re up to, and teching 2x of one card may spell death for you if you guess wrong on which single card to tech 2 copies of. Also, you are almost certain to see whatever you tech in the next 1-3 turns, and with heroes, tech buildings, and add ons always being available expenses, you often want to spend your gold on something OTHER than what you teched anyway. Even if you tech 2x of something, you likely will only have enough gold to play 1 of it when you draw them.

Therefore, it is often wiser & safer to tech 1 of a thing that’ll help against 1 route your opponent might go, and 1 of another thing that would help against a different route. Or 1 expensive thing, and 1 cheaper thing, in case you want to invest in a hero / tech building instead (there isn’t enough gold turn 3/4 to play Rambasa twins AND build tech 2 very easily, so as white I’ll often tech Rambasa Twins AND Martial Mastery or Sparring Partner, so I can decide between teching up, beefing a hero, or the tigers, and always have use for the gold).

I hope that this helps, and I’d encourage you to play some games via the forum; it isn’t the same as playing in person, but it will help a TON in getting you familiar with matchups and how to make these kinds of decisions.

Welcome to the light, I hope you enjoy this game!


One major difference you didn’t touch is a board advantage in Codex leads much more directly to winning the game than one in Magic. In Magic creatures only directly attack your life of which only the last point matters, and you often cede the advantage to your opponent with the plan to take it back later. In Codex there are few specific things that let you pull off something like that, but in general, a player who’s clearly ahead can deny their opponent from having tech buildings or having heroes stick around for more than a turn, and snowballing from there.

While it takes a lot to achieve complete board dominance, the possibility of it should dictate your decisions long before the game gets that far. You simply can’t let yourself be the losing player in that scenario, so if it takes sacrifices to avoid it, you make those sacrifices. Thus reinforcing your position is valuable even when it isn’t immediately making things happen, as it opens up more options for you next turn and restricts your opponent’s.

As a consequence, my assumed default state is that both players will invest all their resources into immediate board position. Not doing so means you either risk being forced to make suboptimal plays to salvage the board, or give up an opportunity to force your opponent’s hand. Anything that deviates from this baseline has a large opportunity cost and you better have a clear plan on how it’s making up for it in immediate future.

This is why I’m not much of a fan of Rich Earth for example - on paper it should be a great play on an open board where you can get away with it, but the opportunity cost is not spending that gold on units. If you spent those 2 gold on a hero or a Tiger Cub instead, your opponent now no longer has an option of just sending a hero out there on its own, and in general has to prioritise keeping the board manageable over making what would be the most efficient plays for them in a vacuum. That type of advantage is hard to quantify, but I believe most of the time it would end up being more than 1 gold a turn. I do think Rich Earth is probably the right play in some scenarios, but always erring on the side of more board presence when unsure is a solid guideline.


I’d echo this. There are lots of people on the forums that are happy to play newbies and help them get better at the game. The play-by-post format helps quite a bit because you can record your decisions as you go and then review them with your opponent afterwards. I learned quite a lot from @FrozenStorm kicking my ass and then explaining very nicely how he did it :slight_smile:

1 Like

Lol that’s kind of you to say @Barrelfish, I’ve enjoyed our various series and tournament games.

@StrixVaria I do think the recorded nature of Play by Post helps a ton in analyzing decisions post-game for the purposes of learning, and I am more than willing to play new players and offer advice post-game.

I invite you to select any matchup you’re curious to try out and play with me on this forum, and I while I am not at all the best player around here, I do play pretty often and enjoy theory crafting post-game on where both players could have done better.

If you don’t have a particular matchup in mind, I do honestly believe Red vs Green is an excellently balanced, very intricate matchup that helps teach the value of Spells and Heroes vs Teching. See this thread for an example of two games my brother and I played against one another, finding various strategies

I would not recommend starting with Blue, especially not versus Black :wink:


I could try play-by-post to get more games under my belt, sure. Having not played a full 3 vs. 3 matchup yet (only Bashing vs. Finesse, as I mentioned above), I’m a little overwhelmed by the idea of trying to keep track of everything. What tools do you use for things like randomizing deck order, keeping track of what’s in what zone, etc? Is it all manual?

I have to admit, when I first read through the cards, Black felt pretty oppressive. I’m not surprised to hear that it’s a rough matchup for blue.


Tracking game state varies from person to person. I use Vassal with my print and play assets imported. Others use table top sim or track it with real life print and play assets on a free desk in their home.

If you don’t have any of that, I’d recommend this google sheet @zejety made I know he and a few other users like Google Sheets for being able to see their deck / discard state on mobile.

1 Like

This is really, really important. Because of the direct unit attacking, I think Codex is much, much closer to Hearthstone (or the WoW TCG) than Magic.

I’m a big fan of plotting out what you want your deck (including Hand, Discard, Deck, and In Play areas) to look like when you hit 10 workers, and calculating which order to tech those cards for the best impact. This could include a slot for “tech in an answer to what my opponent is/might be doing” or a slot for “I want to grab a high cost Tech I unit for one of my second techs, but I’ll decide if that should be Inverse Power Ninja or Rambassa Twins based on the turn 3 board state.” Actual gameplay might cause you to deviate from the plan, but knowing that you want to grab this with mono-blue:
Turn 2 Tech: Overeager Cadet + Spectral Hound
Turn 3 Tech: Flagstone Garrison + {Free Speech or Injunction, depending on board state}
Turn 4 Tech: Drill Sergeant + Overeager Cadet
Turn 5 Tech: Drill Sergeant + {Another spell, based on what’s going on with the board, Free Speech, Hallucination, Judgement Day, Community Service, and Injunction are the options}
Turn 6+ Tech: Air Hammer + Additional cheap units and/or spells, if needed.
Workers (in priority order): Bluecoat Musketeer, Jail, Porkhand Magistrate, Manufactured Truth, no more than one of Traffic Director/Spectral Aven/Building Inspector, Lawful Search

Is a big help in spotting flaws in the plan, or places where you might be overloading your deck with too many high cost or low impact things. For example, this gameplan is going to be very vulnerable to fast pressure backed by a targeting effect to kill the Spectral Hound / Spectral Aven, since I have basically no strong Tech I things in the deck, and need to get Tech II down at 8 workers, and keep it alive. With that information, you can decide if this plan is right for the matchup (hint: don’t try this against black starter with access to Demonology), and maybe do something completely different.

1 Like

Codex is a lot less about “cost curve” than MtG/Hearthstone, but you still have your tech curve - skipping workers before you have 8 or 10 is gonna slow that down. (if you miss t1 you’re in trouble, if you miss t2 for too long you’ll be dead, but if you go for t2 too soon you’re probably dead too)

Yep, I was gonna touch on this re: skipping workers early. Being able to hit Tech I/II is pretty key.

Actually, as a long time magic player, the patrol zone was the thing I had to learn to work with the most. Card advantage in magic and in codex roughly worked out the same to me. My penchant for aggro decks meant that I could end up having 0 cards by turn 3 without sealing the win. This is very similar to what can happen in codex if you try to spend your whole hand. That said, the patrol zone can have a major impact on whether you decide to spend that extra gold or card. If your plans require a hero or building to stay alive, then maybe play an extra card from hand into the technician slot. The opponent can choose to leave you that unit, or help you get back to 5 cards in hand. Same for Scavenger.

Coming up with a good play in Codex is primarily about coming up with ways to deal with your opponents patrol and making a patrol of your own that your opponent will have to deal with the way you expect.

And I would also like to reaffirm that playing matches on the forum is a fantastic way to build up knowledge of card interactions. And to always remember sparkshot when patrolling :stuck_out_tongue:


It’s probably more important to consider techs per cycle rather than per turn?

While unit / spell balance seems like a good framework for mixed teching, cost balance is probably important too? Also, some spells function as units by increasing board presence.

1 Like

This thread deserves a bump or maybe even a pin, or maybe we should colab as a community on a strategy FAQ!