Extravagant Replication + Eternal Witness + Capture of Jingzhou

3-card combo · GU

Verdict

Yes — this 3-card loop chains infinite extra turns as long as 5 mana is available each upkeep.

Cards required: 3
Cheapest stack total: $11.13
Color identity: GU
Popularity: 19 decks
Format: Commander

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Extravagant Replication copies Eternal Witness at the start of every upkeep; the token enters and immediately recovers Capture of Jingzhou from the graveyard, and casting it again buys the next turn. The engine lives in Simic shells where Seedborn Muse or mana doubling keeps 5 mana on tap every loop — Kruphix, God of Horizons is the natural home.

Recipe

How it works

Prerequisites

You have enough mana to cast Capture of Jingzhou each turn.

Steps

Cast Capture of Jingzhou by paying its mana cost, causing you to take an extra turn after this one.
Move to your next turn.
At the beginning of your upkeep, Extravagant Replication triggers, creating a token copy of Eternal Witness.
When the Eternal Witness token enters the battlefield, it triggers, returning Capture of Jingzhou from your graveyard to your hand.
Repeat.

Result

Infinite turns; Lock

Variations

Cheaper, tighter, alternate lines

Time Warp or Temporal Manipulation are cheaper 5-mana substitutes for Capture of Jingzhou if the budget for that slot matters. Any extra-turn spell in the graveyard works as the loop target, so Alrund's Epiphany or Part the Waterveil can slot in if the primary piece gets exiled. The lock is airtight once assembled but collapses immediately if Extravagant Replication is removed at instant speed before the upkeep trigger resolves.