401. Zones : Library
401.1.
When a game begins, each player‘s deck becomes his or her library.
401.2.
Each library must be kept in a single face-down pile. Players can‘t look at or change the order of
cards in a library.
401.3.
Any player may count the number of cards remaining in any player‘s library at any time.
401.4.
If an effect puts two or more cards on the top or bottom of a library at the same time, the owner
of those cards may arrange them in any order. That library‘s owner doesn‘t reveal the order in
which the cards go into his or her library.
401.5.
If a spell or ability causes a card to be drawn while another spell is being cast, the drawn card is
kept face down until that spell becomes cast (see rule 601.2h). The same is true with relation to
another ability being activated.
401.6.
Some effects tell a player to play with the top card of his or her library revealed, or say that a
player may look at the top card of his or her library. If the top card of the player‘s library changes
while a spell is being cast, the new top card won‘t be revealed and can‘t be looked at until the spell
becomes cast (see rule 601.2h). The same is true with relation to an ability being activated.
401.7.
If an effect causes a player to play with the top card of his or her library revealed, and that
particular card stops being revealed for any length of time before being revealed again, it becomes a
new object.
401.8.
If an effect causes a player to put a card into a library «Nth from the top,» and that library has
fewer than N cards in it, the player puts that card on the bottom of that library.