Deep dive into pack opening algorithms and probabilities
Lorwyn Eclipsed uses a sophisticated slot-based pack generation system. Each pack contains exactly 14 Magic cards plus 1 token/helper card, for a total of 15 cards. The pack is built slot-by-slot using weighted random selection based on official Wizards of the Coast probabilities. Fable frame, borderless, and extended-art cards are matched using Scryfall’s frame_effects and border_color (e.g. Fable = “showcase”).
The commons slot starts with 7 cards. However, there's a special mechanic that can reduce this to 6 cards.
In 1 out of every 55 packs, one common is replaced by a Special Guest card from the SPG set. When this happens, the pack contains 6 commons instead of 7.
Exactly 3 uncommon cards are added to every pack. Each uncommon slot has a chance to be a special "Fable frame" variant.
| Uncommon Type | Probability per Slot | Notes |
|---|---|---|
| Regular Uncommon | 90% | Standard frame uncommon from ECL set |
| Fable Frame Uncommon | 10% | Special frame treatment uncommon |
This is the primary way to get extra rares or mythics in a Play Booster. The wildcard can be any rarity, with weighted probabilities. It can also upgrade to special treatments.
| Outcome | Probability | Percentage |
|---|---|---|
| Main Set Common | 0.18 | 18.0% |
| Main Set Uncommon | 0.58 | 58.0% |
| Main Set Rare | 0.19 | 19.0% |
| Main Set Mythic | 0.02 | 2.0% |
| Fable Frame Uncommon | 0.02 | 2.0% |
| Fable Frame Rare | 0.009 | 0.9% |
| Fable Frame Mythic | 0.001 | <0.1% |
| Borderless Nonland Rare | 0.01 | 1.0% |
| Borderless Nonland Mythic | 0.001 | <0.1% |
| Borderless Reversible Shock Land | 0.001 | <0.1% |
The wildcard slot has a 21.1% chance of being rare or mythic (19% + 2% + 0.9% + 0.1% + 1% + 0.1% + 0.1%). This is why you can get multiple rares in a single pack!
This slot is always rare or mythic. It's the guaranteed "big hit" in every pack. However, it can also be upgraded to special treatments.
| Outcome | Probability | Percentage |
|---|---|---|
| Main Set Rare | 0.782 | 78.2% |
| Main Set Mythic | 0.136 | 13.6% |
| Fable Frame Rare | 0.046 | 4.6% |
| Fable Frame Mythic | 0.012 | 1.2% |
| Borderless Nonland Rare | 0.009 | 0.9% |
| Borderless Nonland Mythic | 0.001 | <0.1% |
| Borderless Reversible Shock Land | 0.005 | 0.5% |
The guaranteed rare/mythic slot has a 14.9% chance of being mythic (13.6% + 1.2% + 0.1% + 0.5%). This is higher than the traditional 1-in-8 (12.5%) rate because special treatments can also be mythic.
Every pack contains exactly one traditional foil card. This slot can upgrade to rare or mythic, making it another source of extra rares. The card is always foil, regardless of rarity.
| Outcome | Probability | Percentage |
|---|---|---|
| Foil Common | 0.604 | 60.4% |
| Foil Uncommon | 0.298 | 29.8% |
| Foil Rare | 0.065 | 6.5% |
| Foil Mythic | 0.011 | 1.1% |
| Foil Fable Frame Uncommon | 0.01 | 1.0% |
| Foil Fable Frame Rare | 0.009 | 0.9% |
| Foil Fable Frame Mythic | 0.001 | <0.1% |
| Foil Borderless Nonland Rare | 0.01 | 1.0% |
| Foil Borderless Nonland Mythic | 0.001 | <0.1% |
| Foil Borderless Reversible Shock Land | 0.001 | <0.1% |
The foil slot has a 8.6% chance of being rare or mythic (6.5% + 1.1% + 0.9% + 0.1% + 1.0% + 0.1% + 0.1%). Combined with the wildcard slot, this explains how packs can contain 2-4 rares!
Every pack contains exactly one basic land. The land can be default frame or full-art, and can be foil or non-foil. Full-art lands are highly sought after!
| Land Type | Probability | Percentage |
|---|---|---|
| Default Frame (Non-foil) | 0.40 | 40% |
| Default Frame (Foil) | 0.10 | 10% |
| Full-Art (Non-foil) | 0.40 | 40% |
| Full-Art (Foil) | 0.10 | 10% |
Every pack contains exactly one token or helper card from the TECL (Lorwyn Eclipsed Tokens) set. If TECL tokens are unavailable, the system falls back to ECL set tokens.
Each Lorwyn Eclipsed Collector Booster contains 15 Magic: The Gathering cards and one foil double-sided token, for a total of 16 items. Every card in the main 15 slots is either a guaranteed foil or a non-foil rare/mythic slot. Cards come from multiple set codes: ECL (main set), ECC (Commander), SPG (Special Guests), and the final slot from TECL (foil double-sided token).
| Outcome | Probability | Percentage |
|---|---|---|
| Borderless Mythic (ECC) | 0.09 | 9% |
| Extended Art Rare (ECC) | 0.91 | 91% |
| Outcome | Probability | Percentage |
|---|---|---|
| Foil Extended Art Rare (ECL) | 0.304 | 30.4% |
| Foil Fable Frame Rare | 0.272 | 27.2% |
| Foil Fable Frame Mythic | 0.073 | 7.3% |
| Foil Borderless Nonland Rare | 0.052 | 5.2% |
| Foil Borderless Nonland Mythic | 0.042 | 4.2% |
| Foil Borderless Reversible Shock Land | 0.052 | 5.2% |
| Foil Special Guest (SPG) | 0.105 | 10.5% |
| Japan Showcase Traditional Foil | 0.09 | 9% |
| Japan Showcase Fracture Foil | 0.01 | 1% |
| Serialized Bitterbloom Bearer | 0.001 | <0.1% |
| Outcome | Probability | Percentage |
|---|---|---|
| Extended Art Rare (ECL) | 0.377 | 37.7% |
| Fable Frame Rare | 0.337 | 33.7% |
| Fable Frame Mythic | 0.091 | 9.1% |
| Borderless Nonland Rare | 0.13 | 13% |
| Borderless Nonland Mythic | 0.045 | 4.5% |
| Borderless Reversible Shock Land | 0.02 | 2% |
One foil double-sided token from the TECL (Lorwyn Eclipsed Tokens) set.
By design, every Collector Booster has at least one special-treatment card when the set has any. Slots 10 (full-art land), 12 (Commander), 13–14 (non-foil Booster Fun), and 15 (foil Booster Fun) are always filled from treatments when the pool allows. If a pack would otherwise have zero special cards, the builder replaces slot 15 with a random special card from the pool so the pack always has at least one.
Card data comes from Scryfall. We treat a card as “special treatment” if it has frame_effects including showcase, extendedart, or fullart, or border_color = borderless. Fable frame cards are tagged as showcase in Scryfall. For slots that call for a treatment (e.g. Fable frame, extended art, borderless), we try the exact tag first, then any card with a treatment, then any card of that rarity so you still get a card when the set uses different tags.
Our pack builder was run on 100 Lorwyn Eclipsed Collector Boosters. Results:
You can pull up to four or more Fabled Frame cards in one pack when the right slots hit (e.g. 1 foil uncommon + 2 non-foil Booster Fun + 1 foil Booster Fun).
The pack builder uses a weighted random selection algorithm to determine outcomes. Here's how it works:
Example: For the wildcard slot, if the random number is 0.75, it falls in the range 0.76-0.95 (uncommon), so an uncommon is selected.
To prevent duplicate cards in a single pack, the system tracks which cards have already been selected:
Play Booster — built in order:
Collector Booster — 15 MTG cards + 1 token/art, in order: 5 foil commons → 4 foil uncommons (36.4% Fable) → 1 foil full-art land → 1 foil rare/mythic → 1 non-foil Commander (ECC) → 2 non-foil Booster Fun → 1 foil Booster Fun → 1 token/art. After building, if the pack has zero special-treatment cards and the pool has any, slot 15 is replaced with a random special card so every pack has at least one.
For slots that call for Fable frame, extended art, or borderless, we use Scryfall’s frame_effects and border_color:
showcase or fable (Scryfall uses “showcase” for custom frames like Fable)extendedartborderless or showcase, or border_color = borderlessshowcase, extendedart, or fullartIf no card matches the exact treatment, we prefer any card with a treatment (showcase, extendedart, borderless) over a plain card, so you still see special frames when the set uses different tags.
Lorwyn Eclipsed packs can contain cards from multiple set codes:
The system fetches cards from all relevant sets and correctly assigns set codes to each card in the pack.
This is the most common outcome (~73% of packs):
Result: 1 rare, 11 commons, 3 uncommons, 1 foil common, 1 land, 1 token
This happens in ~27% of packs:
Result: 2 rares, 10 commons, 3 uncommons, 1 foil common, 1 land, 1 token
This happens in ~2% of packs:
Result: 3 rares (1 regular, 1 wildcard, 1 foil), 10 commons, 3 uncommons, 1 land, 1 token
This happens in ~1.82% of packs (1 in 55):
Result: If Special Guest is rare/mythic, you could have 2-3 rares+ in this pack!
This happens in <1% of packs:
Result: 4 rares+ (Special Guest + Wildcard + Guaranteed + Foil), 9 commons, 3 uncommons, 1 land, 1 token
Every Collector Booster has 15 MTG cards + 1 token/art. A typical pack:
Result: 5 rares/mythics minimum, 11–12 foils, at least one special-treatment card
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