War
War is a card game for two players. It uses a standard Western 52-playing card deck. It is most often played as a children's game, because of its simplicity.
How To Play
Each player is dealt half the deck, and both players play simultaneously. Each player shows one card, and whoever has the higher card takes both cards shown and places them at the bottom of his deck. Aces can be high or low, which should be decided before the game begins. In KardsGT aces are always low. In case of a tie, both players play three face-down cards and one face-up card, and these face-up cards decide who will receive all the cards. If there is another tie, the process is repeated, etc. In all cases of ties, face-down cards are exposed before being collected. In some variations, smaller numbers of face-down cards are played (for example, one card is placed face down, while the second is played face up). In one bloodthirsty variation, the number of face-down cards equals the pip value of the cards, with face cards being ten and ace eleven.
Whoever has no card to play when they are required to play one is the loser. In KardsGT this will decide the loser as well. In one other variation, a set number of ties won will decide the winner of the game. In KardsGT we combine this variation with the previous version. The number of ties needed to win is three. Some variations will have the winner being the one who is able to get rid of all his cards first.
To keep with the theme of the game we call the number of cards each player has soldiers. Each phase where a player places cards face up we call a battle. Of course when there are ties, they're called a war.
Strategy
War seems to be a game of chance. However, a player with an excellent memory can improve upon his or her chances of winning by ordering the cards that the player wins in rounds. This is best demonstrated with an example, suppose Alice is playing to beat Bob. The game begins with Bob beating Alice's 6 with a 10. Alice notices that Bob collects the two cards and puts them on the bottom of his deck with the 10 on top of the 6. In the next round, Alice beats Bob's 8 with a jack. Alice now collects the two cards and places them at the bottom of her deck with the jack on top of the 8 so that the next pass through the deck will begin jack beats 10 (Alice collects), 8 beats 6 (Alice collects again). If Alice had instead placed the 8 over the jack, the next pass through the deck would go 10 beats 8 (Bob collects), jack beats 6 (Alice collects), which is not as beneficial to Alice.
However, over the long-term, as the deck sizes change (as both players collect cards) and as more and more cards are revealed, it becomes extremely difficult, indeed, nearly impossible, to implement this strategy. Only a player with an extremely good memory and the ability to visualise extremely quickly card positions in both decks will be able to consistently implement this strategy over the course of a game.
Something analogous to natural selection occurs in war: if you have fewer cards they tend to be of higher quality. Conversely, as you accumulate cards, they become weaker. The rule for handling ties mitigates against this problem somewhat, however.