The remedy for some infractions in this document includes shuffling the randomized portion of the library.
Some infractions in the IPG instruct to shuffle or randomize a library as part of the fix. If they do, use these instructions.
This requires first determining whether any portion of the library is non-random, such as cards that have been manipulated on the top or bottom of the library, and separating those. Check with both players to verify this, and check the graveyard, exile, and battlefield for library manipulation cards, such as Brainstorm and cards with the scry mechanic.
When instructed to randomize the library, we don’t want to lose parts of the library that have been seen and intentionally ordered. Be sure to ask the players if any cards are known, but given player memory is not always perfect, check all the zones for cards and effects that might have ordered or unordered (like fetch lands) parts of the library.
Once the library has been shuffled, any manipulated cards are returned to their correct locations.
Separate the cards that are known, keeping the cards face down and hidden and have the players shuffle the part that is unknown, then add the known cards back to where they are supposed to be.
Shuffles perfomed by a judge as part of a remedy are not considered shuffles for game purposes.
Sorry Cosi’s Trickster. Note that even though this sentence says “performed by a judge” it’s not recommended for a judge to shuffle the library if an infraction calls for the library to be shuffled. Let the player shuffle and present.