How should I determine how many lands of each different color to put in my deck?

Question

Situation: You've built your at least 2 color deck, know exactly what number of lands you want in it, but don't know how many to put in of each basic-land type.

How do pro-players figure this out? Obviously it seems like a deck that is about 50-50 color-wise would have equal numbers of each basic-land for those colors, but what if the deck is 60-40, 70-30, 80-20, etcetera? Or perhaps its a tri-color deck with a 40-30-30 or a 50-40-10 color distribution? Obviously it will depend on the mana-curve and the cards in the deck, but I'm just looking for some general guidelines.

Not getting any land in your side-color is bad, but not getting any in your main color is even worse. How do you manage these problems to get the best chance of success?

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This question addresses how many lands to put in a 40-card deck, and This one addresses the general issues of building a multi-color deck but I'm specifically interested in color distribution of lands. It would be awesome if answers could address both 40 and 60 card decks. I'm talking only about basic lands, as I believe addressing the entire issue of "What lands should I put in my deck?" is far too big for one question.

Answer 1

As an unscientific method for quickly throwing lands into a draft deck, I could up the number of coloured mana symbols in the casting costs of my cards, and use the results as a ratio to choose my lands. So, if my deck has 20 white mana symbols and 10 blue mana symbols, and I need to select 17 lands, I'd typically be thinking about 11 Plains and 6 Islands.

Though of course it's not quite as simple as that. You also need to factor in coloured activation costs, of course; and then, consider when you need your different colours of mana. In the example given above, if many of the white cards cost 4W or 5W, and all the blue cards cost U or UU, then evidently I need to draw my islands early and can get away with drawing plains later on. That sounds like a pretty peculiar deck, but if for some reason it did exist you could easily be considering even 9 Islands and 8 Plains.

Another example: suppose your deck is pretty much mono-white, with a red splash. Your red mana symbols may be less than 10% of your total mana symbols: you may even only have one red card! Even so, it might not serve you well to dogmatically have 1-2 Mountains and 15-16 Plains. 12 Plains should be more than enough to run your white spells off (assuming none of them cost WWW, anyway!) and you can make up the difference with 5 Mountains, to make sure you have a good chance of playing that red spell in any game you draw it.

Unfortunately I don't think there's any simple magic formula for answering this question: it's just the sort of thing that becomes more and more intuitive the more Magic you play. But one last tip: if you're playing a lot of Limited games where your mana is letting you down, consider the possibility that it might not be your choice of lands that's letting you down at all - maybe you should be trying to assemble decks that are less ambitious about the range of spells they are trying to play!

Answer 2

Building mana bases is a mix of art and science. Fundamentally, mana is the biggest resource constraint in a Magic deck, so your land choices are just as important as your spell choices during deck design.

Deckbuilding isn't just about picking spells for your deck, but also about setting up lines of play. As such, your mana base isn't just about what but about when.

Quick and dirty basic land distribution

When I'm pressed for time (e.g. in Limited) or just throwing together a rough draft of a deck, this is my approach:

• Count mana symbols, not cards. A card costing 2WWW has the same converted mana cost (5) as a card costing 4W, but you'll need to play many more white mana sources to be able to cast the 2WWW card reliably. Counting colored mana symbols in cards is a way to account for this. Some online deckbuilding tools (e.g. TappedOut) do this by default.
• "Color screw" is awful and you should take pains to avoid it. Therefore, if you have uneven color requirements, make the mana base a bit less skewed than the color distribution of your spells. For example, if you're running 70-30 red/white, your might do 60-40 mountains/plains. Most costs have a colorless component, so having a few lands of your "secondary" color on the field shouldn't significantly slow down your "main"-color spells.
• By the time you get to playing your six-drops, you'll have seen something like a quarter of your deck; in contrast, you've got at most 8 cards when it's time to make your first-turn play. If you rely on a certain color heavily in the early game, play more of the matching lands to support it.

Basic lands will only get you so far

If you have a deck that wants to play Grand Abolisher (WW) on turn 2 and Chandra's Phoenix (1RR) on turn 3, no combination of basic lands is going to allow that. You can play cards like Rampant Growth and Evolving Wilds for "color fixing", but the larger problem here is a lack of "color depth" -- the ability to make different combinations of colors with the same couple of mana sources. Building a multi-color deck using only basic lands limits your ability to reliably make use of cards with heavy color commitments, which are often some of the strongest effects for their CMC.

Answer 3

There is no definitive formula. Although you specifically ask about color combination it is just part of the bigger problem that is land distribution in a deck.

As @thesunneversets also mentioned, this is the sort of thing that (at least so far) has no simple answer. It is a skill that is refined as you play more and more. Even so, some important questions you have to ask yourself:

1) How many cards of each color (obviously);

2) How many cards that cost more than one colored mana - i.e. if some cards have RR in their cost you have to get two red mana at the same time before you can play those cards.

3) How many one/two casting cost cards of each color - i.e. if all your one drops are red cards, you probably want to make sure you have red mana in your first turn;

Highlighting #3, I would also say this isn't so much a problem of the number of cards in a deck (or format) but a problem of general game plan.

Example: a UR Storm deck in modern only needs red mana to win, but generally packs more blue mana just because it's game plan is to start the game playing cheap blue draw spells in the first turns. All the library manipulation also assure the deck sees the 1/2 red mana sources it needs in a single game.

Another example: Richard Bland's top 8 decklist in GP San Diego 2011 features only 2 really powerful cards that need red: Kessig Wolf Run and Devil's Play. Using Traveler's Amulet and Caravan Vigil he could have two extra "virtual" Mountains, without stressing his manabase that much. Plus, both are late game winning cards, so a single Mountain to enable the strategy seems more than enough.