MTG Formats
Dandan: The Shared-Deck Format
Two players, one library, one graveyard, and one creature in the entire format. Deckbuilding is finished before you sit down, which leaves nothing to separate the players except how well they play.
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What Dandan is
Dandan, also known as Forgetful Fish, is a two-player format in which both players draw from a single shared 80-card library and use a single shared graveyard. The decklist is fixed and agreed in advance. It is mono-blue, its lands are Islands, and the only creature in it is the card the format is named after.
It began as a curiosity and became a genuine competitive niche, played at conventions, over webcam and on Magic Online. Nobody builds a deck for it, so nobody can buy an advantage in it, which is close to unique among Magic formats.
Every other format asks two questions: did you build the better deck, and did you play it better. Dandan deletes the first one. Both players have the same deck, in the most literal sense available, because it is the same deck.
the reason people who play it keep playing it
The rules
One 80-card library sits between the two players. Both draw from it.
One graveyard, shared. Anything either player discards, mills or loses goes to the same pile, and both players' cards count for effects that look at graveyards.
Each player starts at 20 life.
You lose at zero life, or when you would draw from an empty library. The second clock is shared, so a card you draw is a card they cannot.
The decklist is agreed before play, not built. Community lists exist and vary only slightly.
Everything else is ordinary Magic. It is the shared library that does the work: it turns library manipulation into interaction, and it makes every "put it on top" effect a decision about your opponent's turn as much as your own.
The deck
Ten Dandans, eight Memory Lapses, four Accumulated Knowledge, a spread of two-ofs that manipulate the top of the library, and Islands. That is the format.
Dandân ↗
The format's only creature, and there are ten of them in the deck. A 4/1 blue Fish that cannot attack unless the defending player controls an Island, and is sacrificed if you control none. Since the deck is all Islands, both clauses are always on.
Memory Lapse ↗
Counter a spell and put it on top of its owner's library instead of the graveyard. Eight copies, in a format with one shared library, so it counters their spell and decides their next draw at the same time.
Accumulated Knowledge ↗
Draw a card for each Accumulated Knowledge in every graveyard, plus one. With a shared graveyard, both players' copies count for whoever casts one, so the fourth is drawing four cards.
Brainstorm ↗
Draw three, put two back. In a shared library, putting two cards back is also stacking your opponent's next two draws, which is the format's central trick.
Ten copies of the creature is not an arbitrary number: it is the count the community settled on because it keeps the board occupied without both players drowning in 4/1s that cannot attack. The Accumulated Knowledge count matters for the same reason, since the shared graveyard means each copy cast makes the next one bigger for whoever draws it.
Some of the format's most-loved cards are ones no constructed deck would ever look at. Because every creature in the game is a Dandan and every land is an Island, a card that changes a land type reads as a one-mana board wipe, and a card that changes a colour word reads as removal. That is the sort of thing a fixed decklist lets you build for, and part of why the list has stayed stable for years.
How it actually plays
One exchange, and why it is not simple
You cast a spell. Your opponent answers with Memory Lapse, countering it and putting it on top of the shared library.
That card is now your opponent's next draw, not yours, because they drew it on their turn. They have spent two mana to counter your spell and hand themselves a card.
Unless you have a way to draw first, or to move the top of the library, in which case they spent two mana to give you a spell back.
Every top-of-library effect in the deck creates this decision, and there are a lot of them. Knowing what is on top and who draws next is most of the skill.
Count the library out loud. Both players run out of cards at the same moment, but only one of them has to draw first. Games are regularly decided by whether you can force an extra draw three turns before the deck runs out.
Attacking is a decision, not a default. Two Dandans staring at each other is a stalemate, since a 4/1 trades with a 4/1 and neither player gets more of them than the other. Attacking usually means you have a plan for what happens after the trade.
Your discards help them. The graveyard is shared, so a card you throw away is a card their Accumulated Knowledge counts. There is no such thing as a private resource in this format except the cards in your hand.
Why play it
Two reasons, and they are both practical. It costs almost nothing, because one deck serves two players and most of the cards in it are old commons. And it removes deckbuilding entirely, which makes it the cleanest test of play skill in Magic: if you lost, it was not the deck.
It also travels well. One deck box covers a game, so it is the format to have in a bag for a queue, a train, or the hour before everyone else arrives at Commander night. If you like the idea of a cheap format that stays cheap but want something with real deckbuilding in it, the two neighbours are Pauper and Penny Dreadful.
Frequently asked questions
What is Dandan in MTG?
A two-player fringe format in which both players draw from the same 80-card library and share one graveyard. The list is fixed and agreed in advance, it is entirely blue and Islands, and the only creature in it is the card Dandan, which the format is named after. Players start at 20 life and lose at zero life or by being unable to draw.
Why is Dandan called Forgetful Fish?
Because of its two most numerous cards. Dandan is a Fish, and the deck plays eight copies of Memory Lapse, so the format is a fish that keeps forgetting things. The two names are used interchangeably.
How does sharing a library work?
There is one deck on the table and both players draw from it. Whatever you put on top with a Brainstorm or a Memory Lapse is the card your opponent draws next, and whatever you draw is a card they now cannot. Card advantage stops being about accumulating cards and becomes about controlling one queue.
How many Dandans are in the deck?
Ten, which is the number the community settled on. Fewer and the games stall out with nothing on the board; more and both players flood on 4/1s that cannot profitably attack into each other. It is the clearest example of how tuned a fixed decklist can be.
How do you win a game of Dandan?
By reducing your opponent to zero life with repeated Dandan attacks, or by being the player who is not forced to draw from an empty shared library. Both clocks tick at once, which is why the format's decisions are almost all about the top of the deck rather than about the board.
One deck, two players, every game logged.
TurnZero HQ tracks life totals and results for any format, including the ones with a single library in the middle of the table.
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