Expand a Cube Without Diluting It: 360 to 540

To expand a cube well, add cards to roles, not to the pile. The failure mode is familiar: a tight 360 grows to 540 over a year of “this is too good to leave out,” and the result drafts worse than the 360 did. Aggro gets thinner, lanes get vaguer, and the owner cannot say why. The cause is almost always the same. The new 180 cards were chosen for quality and the old 360 was chosen for structure, and structure is what a draft feels.

Here is how to grow a cube so that the bigger version is a bigger version of the same thing.

Should you expand at all?

Three good reasons and two bad ones.

Good: your group regularly seats more players than the cube supports. Good: the group has drafted the same list so many times that picks are automatic and they have asked for variety. Good: you want to support a lane or two that the current size cannot fit without cutting something that works.

Bad: you have a stack of cards you like and nowhere to put them. Bad: a bigger cube feels more serious. Neither of those is a design reason, and both produce the diluted 540. Our 360 vs 540 piece has the full case for each size; if none of the good reasons apply, stay where you are and draft more.

If you do expand, pick the target size first. 360 to 450 is a 25 percent increase and the easiest to keep tight. 360 to 540 is 50 percent and the most common. Going straight from 360 to 720 doubles the cube and is rarely a good idea in one step; do it as two expansions a year apart.

Scale every section by the same ratio

This is the whole method in one sentence. If the cube is growing by 50 percent, every section grows by 50 percent, and within each section every role grows by 50 percent.

A worked example, 360 to 540:

Now go one level down. If white at 360 had 8 one-drops, 10 two-drops, 6 removal spells, and 2 wipes, then white at 540 has 12 one-drops, 15 two-drops, 9 removal spells, and 3 wipes. Your spreadsheet should already have these counts per role; if it does not, the sections and slots article explains why building it first makes the expansion almost mechanical.

Owners resist this because the added cards feel forced. Finding four more white one-drops is less fun than adding four more white four-drops, because the four-drops are more exciting cards. That is exactly how aggro dies during expansions. The ratio is what keeps the cube’s proportions, and proportions are what drafters feel.

Deepen lanes before adding lanes

A 360 might support eight lanes at about twelve cards each. The temptation at 540 is to add two more lanes. The better move is to deepen the eight you have to about eighteen cards each, and only then ask whether there is room for a ninth.

The reason is density. A 540 opens two thirds of itself per draft. A lane that was twelve deep at 360, where every card showed up, needs eighteen at 540 to show up twelve on an average night. If you add lanes instead of depth, every lane in the cube becomes less reliable at once, and the draft turns into good-stuff.

Practical order of operations:

1. For each existing lane, list its signposts, payoffs, and enablers. Add cards until the lane at 540 has the same expected count on the table as it did at 360.
2. Check that no lane depends on a single card. At 540, that card is in the box a third of the time.
3. If, after step one, there are still unfilled slots in the colors, consider one new lane. Give it the full count. A half-supported new lane is worse than none.

Our archetype density article has the numbers for how many lanes a given size holds.

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Add the lands first

Lands are the section owners under-expand most often, because lands are boring to add and expensive to buy. The result is a 540 with a 360’s fixing, where three-color decks suddenly stop working and nobody connects it to the expansion.

If the 360 had two cycles (20 duals), the 540 needs three (30) to give drafters the same fixing per draft. If it had one cycle, it needs fifteen. Add these before anything else, because they decide what the rest of the cube is allowed to be. If the budget does not stretch to another full cycle, use a cheaper cycle (pain lands, check lands) or proxies rather than skipping it.

Utility lands scale the same way. Six at 360 becomes nine at 540. Basics are separate, and you probably already have enough.

Where do the new cards come from?

Three sources, in order of preference.

The cube’s own bench. Every owner has a short list of cards that were cut from the current size for space. These were already judged against the cube’s roles. Start there.

The role list’s gaps. For every role whose count is short after the ratio pass, search for the best available card at that mana value. This is slow and it is the work. Use CubeCobra’s analysis and other public lists at the target size for ideas, then judge against your own cube.

New sets. Last, not first. New cards are exciting and exciting is how expansions go wrong. Add a new card only when it fills a role gap better than the bench or the search did.

A card that is strong but fits no role gap goes on the bench, not in the cube. You will be glad of the bench next time.

How do you test an expansion?

Three drafts minimum, with notes.

Before the first draft, write down what you expect to change: “aggro should be as reliable as before, three-color decks should appear about as often, the blue-black lane should be drafted at least once.” These are testable.

After each draft, check three things:

• Lane coverage. Which lanes were drafted? Which were open and ignored? A lane that nobody drafts three times running is thin or badly signposted.
• Deck quality at the bottom. Look at the weakest deck at the table. In a well-expanded cube it looks like the weakest deck did before. If it is noticeably worse, the new cards are padding.
• Last picks. Collect the cards that went pick thirteen or later across all packs. If the same cards appear each draft, they are the first cuts.

Expect to swap ten to twenty cards after the test period. That is normal. An expansion is not finished when the count reaches 540; it is finished when three drafts in a row play the way the 360 did, with more variety.

Two shortcuts that work and one that does not

Works: expand in two steps. 360 to 450, draft it for two months, then 450 to 540. Each step is small enough to debug. Our piece on shrinking a cube argues that 450 is a good place to stop entirely.

Works: expand as a module. Build the added 180 as a separate, labeled set that can be removed. If the 540 plays worse, you are one box away from the 360. If it plays better, fold it in. This is the thinking behind modular cubes, and it makes expansion reversible.

Does not work: expand by adding whatever you open. Adding a few cards per set with no cuts is how a 360 becomes a 410, then a 470, then a 540 that nobody designed. If you are not expanding on purpose, keep the count fixed and make every add a swap.

The game is the reason. The people are the point. A bigger cube should mean more of the same game for the same people, not a different game they did not ask for.

FAQ

How do I expand a cube from 360 to 540?

Multiply every section and every role count by 1.5, add lands first, deepen existing lanes before adding new ones, fill gaps from your bench and targeted searches, and test over at least three drafts.

Does a bigger cube need more lands?

Yes, in proportion. Two dual cycles at 360 become three at 540, or drafters see noticeably less fixing per draft and three-color decks stop working.

Can I add cards to my cube without cutting any?

Only if you are deliberately expanding to a new target size. Otherwise, every add should be a swap, or the cube drifts in size and loses its structure.

How long does it take to expand a cube?

Choosing the cards can take a few weekends. Testing and tuning takes three to six drafts, so plan on one to two months before the bigger cube feels settled.

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