A player's hand (
Any cards that you draw are added to your hand. The normal hand size limit is six, so during your End Phase if you have more than six cards in your hand, you must discard cards until you have six cards left. Some cards are able to increase the hand size limit, while others can decrease it.
Certain card effects can interact with cards in players' hands. For example, "Spirit Reaper" can discard 1 card from the opponent's hand as part of its effect, and "Exchange" allows you to swap one card from your hand with one card in your opponent's hand. Many card effects have costs that require discarding a card(s) from your hand, such as "Raigeki Break", and you cannot activate such effects unless you have enough cards in your hand to pay the cost.