CS2 peilių retumas: kaip iškritimo tikimybė, dažymų pasiskirstymas ir float kartu sukuria tikrą retumą

Pulling a knife from a CS2 case is the marquee outcome of the entire opening experience: a single 0.26% probability event that yields an item typically worth 50–500× the case-and-key cost. But that headline number — 1 in 384 — hides a much more granular distribution. Within that 0.26%, the specific knife type, finish, exterior tier, and StatTrak status combine into a probability tree where the rarest leaves are individually one-in-fifty-thousand events or worse.

The 0.26% Special tier

Every standard CS2 case allocates 0.26% probability to the Special (Gold) tier, which contains the case's knife or glove pool. This rate is fixed across the standard active-drop and discontinued case format — modifications appear only in operation cases and very early CS:GO-era cases that predate the modern format.

Knife type distribution within the Special tier

Once a Special-tier roll occurs, the specific knife type and finish are selected with uniform probability across all knife-finish combinations available in the case. Each case typically contains 19 knife types — Bayonet, Karambit, M9 Bayonet, Butterfly, Talon, Skeleton, Survival, and so on — with each type having multiple finishes (Doppler, Fade, Marble Fade, Slaughter, Crimson Web, etc.) that vary by case era.

If a case has 19 knife types × 5 finish styles, that is 95 distinct finish combinations. Each is selected with probability 1/95 inside the Special tier. Multiplied by the 0.26% Special rate, the chance of any specific knife-finish lands at approximately:

Layering on float and StatTrak

The float roll splits each knife-finish into its five exterior tiers with the standard 7/8/23/7/55 distribution for unrestricted-range items. The StatTrak roll adds an independent 10% probability layer. The full probability of a Factory New StatTrak Karambit Doppler in a case where Karambit Doppler is a possible drop, assuming standard 95-finish allocation:

These compounded events are what create the multi-thousand-dollar price tags on top-end knives — they are not arbitrary; they reflect the long tail of a deeply nested distribution.

Why some knives are 'rarer' than the math suggests

The base probability assumes the case is still openable and contains the knife in question. In practice, several finishes are now available only from discontinued cases — meaning new supply is structurally limited to whatever existing case inventory remains in player hands. For these:

• Discontinued case finishes receive no new supply except via the slow opening of remaining case stock.
• Pattern-rare variants within a finish (rare Doppler phases, blue-gem Case Hardened patterns, low-pattern Marble Fades) are selected by an additional uniform roll on the pattern index that is independent of the float and tier.
• Souvenir knives do not exist — no knife in CS2 has ever been a souvenir variant — so the souvenir-rarity layer that compounds on weapons does not apply to knives.

Pattern indices and how they compound

Each skin instance receives a uniformly random pattern index in the range 0–999, independently of all other rolls. Most finishes are visually identical regardless of pattern index, but several are highly pattern-dependent:

For pattern-sensitive finishes, the headline rarity drops by another 1–2 orders of magnitude. A Ruby-phase Karambit Doppler is approximately 0.4% of all Karambit Dopplers, which on the underlying 1-in-36,500 baseline produces an effective rate of approximately 1 in 9 million for any specific knife-phase combination.

The composition of the 'top knife' market

Across the past 24 months of third-party transaction data, the population of knives priced above $5,000 is dominated by four overlapping categories:

1. Discontinued case knives — particularly Operation Bravo, Operation Wildfire, and other pre-2017 cases — that no longer receive new supply at scale.
2. Doppler gem phases — Ruby, Sapphire, Black Pearl, and Emerald (Karambit only).
3. Tier-1 Case Hardened patterns (e.g., #661 Karambit Case Hardened, also known as the original 'blue gem' standard).
4. Sub-0.001 float examples on otherwise-common high-tier knives (lowest-float Karambit Fade FN, lowest-float Butterfly Crimson Web FN, etc.).

Practical takeaways

• The Special tier is 0.26% — the same number across all standard cases.
• Within the Special tier, knife-finish selection is uniform — there is no internal weighting between knife types.
• Pattern-sensitive finishes add a third roll that makes some specific outcomes effectively 1-in-10-million events.
• Discontinued case knives accrue value over time because no new supply enters; active-case knives rarely top the market in their first 18 months.
• Top-tier knife prices reflect compounded scarcity, not arbitrary collector hype — every premium maps back to a probability number.

Knife rarity is a multiplicative system: the headline 0.26% is just the entry condition, and each subsequent layer (knife type, finish, exterior, StatTrak, pattern) divides the population by another factor of 10–100. The handful of knives that command five- and six-figure prices are not arbitrary outliers; they are the literal terminal nodes of a probability tree where every fork was the rarer option, and pricing them correctly requires multiplying every layer with appropriate care.