Binding of Isaac: Rebirth Wiki

(in Afterbirth † and Repentance)

D1 is an unlockable activated item added in The Binding of Isaac: Afterbirth †.

Effect[ | ]

  • Duplicates 1 random pickup in the current room, including Cards, Runes, ChestChests, and trinkets.
  • (in Repentance) Duplicated pickups may not be identical to the original; for example, a duplicated card may be a different one than the original.

Notes[ | ]

  • It is possible to duplicate ShopShop pickups that have not been purchased yet.
  • With Collectible Car Battery iconCar Battery, it is possible to infinitely generate Lil' BatteryLil' Batteries from a single Lil' Battery.
    • (in Repentance) While it's still possible to generate infinite batteries with this synergy, it is slow to do so since mostly Micro Batteries will spawn. The occasional Lil' Battery or other battery spawn is needed to build up the battery pile.
  • (except in Repentance) Rune of JeraRune of Jera can not be duplicated.
  • (except in Repentance) Mimic chest RepentanceMimic Chests will not be duplicated until their spikes are exposed.
  • (except in Repentance) Opened chests will be duplicated into an unopened copy.
  • (except in Repentance) A normal Chest may be duplicated into a Red Chest or a Mimic Chest.
  • (except in Repentance) A duplicated trinket is mostly useless, as you cannot pick up two of the same trinket even with Collectible Mom's Purse iconMom's Purse, Collectible Belly Button iconBelly Button, or Collectible Smelter iconSmelter.
  • (except in Repentance) In combination with a 48 Hour Energy pill and Paper ClipPaper Clip, the initial Locked Chests on ChestChest can be infinitely duplicated and opened.
  • (except in Repentance) In Greed Mode, if a Lil' Battery appears in the ShopShop and a 2 of Diamonds2 of Diamonds is acquired, infinite money can be gained by duplicating the Two of Diamonds.
  • (except in Repentance) By dropping a card, rune, or pill in a room with no other pickups, then using D1, this item can function similarly to Collectible Blank Card iconBlank Card and Collectible Placebo iconPlacebo.
    • (in Repentance) By dropping a card, pill, or trinket in a room with no other pickups, then using D1, this item can function similarly to Collectible Deck of Cards iconDeck of Cards, Collectible Mom's Bottle of Pills iconMom's Bottle of Pills, or Collectible Mom's Box iconMom's Box (But without the luck up or doubled trinket effects).
  • (in Repentance) A duplicated card has a very rare chance to turn into a Dice ShardDice Shard, Cracked KeyCracked Key, or Emergency ContactEmergency Contact; however, these will always duplicate as themselves instead of duplicating as a card.
  • (in Repentance) A duplicated Gold Pill will turn into a random Pill chosen from the Pill Pool.
  • When duplicating any type of Chest, the contents of the original Chest will be rerolled. This can be seen with Guppy's Eye.

Synergies[ | ]

  • (in Repentance)Collectible Book of Virtues iconBook of Virtues: Spawns a white six-sided die wisp on the middle ring. An extra wisp spawns if no pickups are duplicated.
  • (in Repentance) Character Tainted Lost iconTainted Lost: Duplicated cards have an increased chance to be Holy Cards.

In-game Footage[ | ]

Trivia[ | ]

  • (except in Repentance) D1 is the only die item that doesn't re-roll anything.
    • (in Repentance) The D1 now creates randomized pickups, meaning that the description is more accurate to the item's effect.
    • (in Repentance) As an exception, Collectible Spindown Dice iconSpindown Dice and Collectible D10 iconD10, although they technically do re-roll items/enemies, have a controlled and consistent result.
  • D1 is the only standard die item that doesn't have the respective number of sides as outcomes, but rather, just a D6 with all sides having singular pips. Rather, an actual D1 would be more accurately pictured as a Mobius strip or a sphere.