Microsealed is a Magic: the Gathering format invented in 2013 by Jason Waddell, the inventor of Grid Draft. I've played it constantly for over a year now, and it's become my favorite way to play the game. The original article Jason wrote about Microsealed is lost to time only available via Wayback Machine (see below), so I wanted to preserve some kind of guide here, and encourage more people to try it out.

Here's how Jason sums it up:

Each player is given a stack of 90 non-land Cube cards, and the two of you build 15-card decks (15 cards, not 15 spells) to jam against each other. The winner stays and the loser retires the cards from their deck and goes back to their card pool to build a new creation to dethrone the champ. The first player to win 4 matches wins.

How to play

• Gather 90 random non-land Cube cards (or six booster packs!) per person, plus basic lands.
• Build a deck of exactly 15 cards to play a best-of-3 match.

The shuffle rule

Any time a player has priority, they may use the following action (as an instant that uses the stack):

“Pay 3 life: Shuffle your graveyard into your library, then put any exiled cards on the bottom of the library in a random order.”

You do not lose the game for drawing from an empty library. You simply take no draw step.

Retiring cards

• After each game, you may sideboard up to three cards from your card pool (including basic lands). Any non-land cards removed from the deck are retired; they cannot be used again.
• After a player loses a match, they retire all the non-land cards from their deck and build a new one from their pool
• If a player wins two matches in a row, their deck is also retired. In this case, both players would build new decks.

The tutor rule

When searching your library (e.g. with [[Stoneforge Mystic]] or [[Farseek]]), players may search for any card in their card pool. If you search from your collection, ignore printed shuffle instructions. (This can help you ramp for basic lands from outside your deck, with Evolving Wilds etc.)

Note: after the game, you must retire enough non-land cards to return to a 15-card deck for the next game. The tutored cards either stay in your deck or are retired. They don't go back to your collection unless they were specifically fetched by 'outside the game' cards like [[Wish]].

Why play this?

The format feels like a really cool blend of limited and constructed; the decks are consistent and synergistic (a 15-card deck with 1-ofs plays like a 60-card deck with 4-ofs) and a meta develops as you go back to your pool to build something that counters your opponent's newest deck. It's a cool way to go deep on a format.

With only 9-10 non-lands in a deck the size of a sideboard, you can go really deep on synergy. Starting hand size is still seven, meaning you draw almost half your deck right at the start. Mana-screw/flood doesn't really happen. And you can build around niche combos knowing you'll get all the pieces sooner or later.

The shuffling mechanic adds some fun tension to the game. Per Jason:

After bolting the bird, do you shuffle the Bolt back into your library? Do you shuffle before or after cracking your fetchland? Your opponent casts [[Terminus]] while you have an on-board [[Carrion Feeder]]; which creatures do you not want to go back into the library? Do you want them on the bottom? Do you shuffle afterwards? Shuffle then sacrifice? How many times are you willing to shuffle with [[Sphinx of Jwar Isle]] in play?

It's also a great way to re-use your prerelease pool! Take home your six packs' worth of cards and have a microsealed tournament with a friend. I've had days where I play round after round; I've also left the sealed pools on the side and played one round a night over the course of a week. It's easy to dip in and out of. Four matches can make it a long format, meant to fill a lot of time if you and a buddy are sitting around with hours to kill; you can also play 1-game matches for time considerations, or play till 3 matches won.

Resources

Jason's original article (found on the wayback machine, thanks u/marrowofbone!)

Thread on Jason's Riptide Lab cube forum talking about the format

Rules for a multiplayer round-robin variant

u/lemem's microsealed cube, which includes two nonbasic lands available to each player: a City of Brass that gains your opponent life when tapped instead of draining you, and an Evolving Wilds that fetches for a basic that enters untapped.

Sample decks

Queza Control - This deck created a loop where you play cantrips, drain with [[Queza]], and use the life you gained to shuffle your deck and restart the loop

Aragorn Aggro - A red-white deck that splashes a Forest and Island to run [[Aragorn, the Uniter]]

Obosh Menace - Ikoria's companions sit as a 16th card outside the game, and only retire with the rest of the deck. I used odd-numbered cards to fulfil [[Obosh]]'s requirement, and mutate costs to do things on my even-numbered turns

Let me know if you try out this format! I personally play with MTGO redemption sets, so my experience of this is mainly in single-set limited formats. It's a real passion of mine and I'd love to hear what you come up with!