LJ Idol: Week 2: Deconstruction
It seems fairly simple.
A Magic: The Gathering deck is sixty cards. The land/creatures/non-creature spells split is 20/20/20--though you might want to go as high as twenty-four land. It's something to do with ensuring you have mana at the ready: mana screw has caused the loss of many a game.
The land forms the colour of the deck you're building: plains for a white deck (W), islands for blue (U), swamps for black (B), mountains for red (R) and forests for green (G). Multicoloured decks are possible, though pairing two colours not side by side on the colour wheel makes it more challenging as there are less dual-lands for colours not side by side (a land that will give both types of mana).
Unless an effect is in play, each land in play can be tapped for one mana only, which is then used to pay the mana cost for creatures and non-creature spells. The mana cost is expressed like so: (#) symbol(s). Not every card has a (#), which is colourless--any mana type can pay for that portion of the cost. The symbol(s) are colour specific--so it's pointless running Sun Titan (4WW) in a deck with no Plains.
One must keep the mana costs of cards in mind for a couple of reasons:
1. In general, if you're paying more for a card, it is better than a lower cost card, but there are always exceptions to this. Ember Shot vs Lightnining Bolt is a great one. For 6R, Ember Shot deals three damage to target creature/player and you draw a card. For R, Lightning Bolt deals three damage to target creature/player.
2. You start with twenty life and zero poison counters. Hit zero life or ten poison counters, and you've lost the game.
-- A deck with high cost cards may be really powerful, able to take whatever your opponents throw at you and dish out lots of damage, but it's also useless until you have the necessary land on the field to pay the mana cost.
-- A deck with low cost cards will mean you can put out x one mana creatures every turn (where x is the land you have on the field) and swarm your opponent (attack with so many creatures they can't block all the damage).
In both these cases it would not be surprising if you ended up dead before any plans were executed in full.
There are two questions to ask: Why is this in your deck? And is there another card that can do a better or identical job for the same or less mana cost? (Ember Shot vs Lightning Bolt is a good example: for six less mana you do the same damage to the same targets but lose the ability to draw a card--even so, many people would consider Lightning Bolt a better card.) If you're running mono-coloured decks, keeping the mana cost to colourless/the same colour is also very important [see Sun Titan, two paragraphs ago].
Even when you have your deck sorted and are ready to play it, you're not quite done: there may be cards that just don't work. Your ratio of card types may need fine-tuning. Your black deck may just be perpetually weak against decks that have flying creatures. Or your playing style may need adjusting.
But in the end, it is just a game... and maybe not worth all this analysis.
...yeah, considering I just got enough cards to make my unsorted cards worth four decks when sorted properly into decks, I don't believe that.