Hand advantage

Hand advantage is comparing how many cards you have in your hand, compared to your Opponent.

For example, if you have 5 cards in your hand and your opponent has 2, it can be surmised that, because of the larger pool of cards you have at your disposal, that you have a greater chance of countering whatever your opponent can put into play, because you have a better hand advantage than he/she does.

Playing cards from one's hand tends to use up hand advantage--an consequence often described by duelists as a comparison of one's hand size after using a card(s) with the hand size before using it. Therefore, many cards (Book of Moon, Dark Hole, etc.) are considered to be -1 because you hand size decreases by 1 card. Cards with discard costs (Back to Square One, etc.) tend to be -2, because hand size decreases by 2 cards after playing them. Most cards meant for drawing (Allure of Darkness, Reinforcement of the Army, Graceful Charity, etc.) are considered neutral or 0, and a small number of cards (Pot of Greed, Preparation of Rites, etc.) are considered +1. As mentioned, most cards have negative hand advantage values, which is why both duelists' hand sizes tend to decrease as a duel progresses. However, this is off-set by the effect each card has on field advantage, which works in a similar way.

Hand advantage and field advantage are constantly compared, and whether any given loss in hand advantage is worth the gain in field advantage is up to the player's opinion. for example, Smashing Ground is a -1 for the user's hand advantage, but confers a -1 on the opponent's field advantage because it destroys 1 of his/her monsters. Different players approve or disapprove of such a trade-off, depending on each individual's style of playing.

Some cards have varying effects on hand advantage, depending on the situation. Morphing Jar sends both player's hands to the Graveyard and then each person draws 5 cards. Such an effect is best used when you have no cards in your hand, so you can make the Morphing Jar effect a +5. If you use it when you have a hand of 5 or 6 cards, you miss the opportunity to drastically increase your hand advantage. The same goes for cards which have variable impacts on field advantage. For example, Lightning Vortex is always a -2 for the user's hand advantage because of its discard cost. But the loss in field advantage to the opponent will depend on how many monsters he/she controls. It is generally better to save Lighting Vortex for a time when it can destroy at least two of the opponent's cards, so that his/her loss in field advantage will at least equal the user's loss in hand advantage. Of course, other factors complicate this decision. Sometimes the opponent has three or four monsters, making Lighting Vortex an obvious choice. Other times, the opponent has just a single monster that might be dangerous if not destroyed. In this case, the user might have to accept the loss of more cards than the opponent if it means taking out a dangerous opposing monster.