.mtgr

Appearance

0018: Opening hand actions and replacement effects ​

Status: Accepted

Context ​

Some cards act before the first turn: Leyline of the Void and Gemstone Caverns begin the game on the battlefield, Chancellor of the Annex is revealed from the opening hand, and Serum Powder replaces a hand during the mulligan process. The spec's pregame section stopped at the mulligan (CR 103.5) and did not say where these actions go or what causes them.

Writing the example also showed a gap that Leyline of the Void makes common: once Leyline is on the battlefield, a card the opponent discards is exiled instead. A move line has one cause, so the file could say the card was discarded by Thoughtseize, or exiled by Leyline, but not both.

Decision ​

  1. Opening hand actions come after every player has kept, the starting player's first, then each other player's in turn order.
  2. They use ordinary statements, caused by the card that allows them: move hand -> battlefield by #N to begin the game with a card on the battlefield, reveal by #N to reveal one, and moves, draws, and counters lines for anything else the card does. Counters a permanent is given as it enters are a counters line straight after its move.
  3. Cards used during the mulligan process (Serum Powder) are written with ordinary moves and draws caused by that card, at the point they are used.
  4. A card not used this way writes no line.
  5. An event changed by a replacement effect keeps its original cause and adds replacement #N, naming the object whose replacement effect applied: move hand -> exile as discard by #18 replacement #15. The line shows what actually happened. Several replacements are listed in the order applied.

Rules basis ​

Checked against the Comprehensive Rules effective 2026-09-25.

  • 103.6: "Once the mulligan process (see rule 103.5) is complete, the starting player may take any such actions in any order. Then each other player in turn order may do the same."
  • 103.6a: "If a card allows a player to begin the game with that card on the battlefield, the player taking this action puts that card onto the battlefield." The card gives the permission, so it is the cause.
  • 103.6b: a card revealed from the opening hand "remains revealed until the first turn begins".
  • 122.6: counters being "put on" an object include those "given counters as it enters the battlefield", so a counters line after the move is accurate.
  • 603.7a: delayed triggered abilities can be created "as a result of a static ability that allows a player to take an action", as Chancellor of the Annex's is. It is an ordinary triggered ability with Chancellor as its source.
  • 118.12a: "[Do something] unless [a player does something else]" means the player may do the other thing. Paying Chancellor's {1} is a choice of the opponent, written with by "Player" (decision 0017), and the payment is a cost of that ability.
  • 614.1a: effects that use the word "instead" are replacement effects. 614.6: "If an event is replaced, it never happens. A modified event occurs instead." The line records the modified event, and replacement records why it differs from what the cause asked for.
  • 701.9a: "To discard a card, move it from its owner's hand to that player's graveyard." With 614.6, only the modified event happens: the card moves from hand to exile instead, and it is still the discard the effect asked for, so as discard stays. (701.9c covers the narrower case of a discard replaced by a move to a hidden zone.)
  • 616.1: when several replacement effects apply, they are applied one at a time in a chosen order.

Alternatives rejected ​

  • A dedicated pregame statement (for example begin-on-battlefield). Rejected: a move caused by the card says the same thing with existing grammar.
  • The replacement effect as the only cause (by #15). Rejected: loses that Thoughtseize caused the discard, which "whenever an opponent discards" abilities depend on.
  • Recording the replaced event and then the change (a move to the graveyard, then a move to exile). Rejected: the replaced event never happens (CR 614.6), so the file would describe a state that never existed.

Consequences ​

  • See examples/opening-hand.md.
  • Choices and payments for a replacement effect (Watery Grave's 2 life) stay as in decision 0017. replacement is only for events whose outcome was changed.