WU leans on Swords to Plowshares to pick off our key creatures and Stifle to counter our key triggers, plus Force of Will and Daze to protect Tamiyo, Inquisitive Student and Phelia, Exuberant Shepherd. Into the Flood Maw is efficient removal for their small threats and dodges their counterspell math by being cheap and flexible. Leyline of the Void, free from an opening hand, only exiles cards headed to an opponent's graveyard, so it never interferes with our own dredge or Bridge from Below engine, while denying any incidental graveyard value they pick up from Snapcaster Mage flashback. Unmask is weak here since they hold up so much free countermagic that a resolved discard spell rarely changes their plan, so we trim it for more resilient threats and answers.