Metin2 Dragon Stone Alchemy: Upgrade Order and Expected-Cost Formula

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Metin2 Dragon Stone Alchemy: Upgrade Order and Expected-Cost Formula

Gameforge's Dragon Stone Alchemy guide identifies seven Dragon Stone types and describes class, purity and level as three enhancement tiers. Its beginner guidance recommends prioritizing class because higher classes can provide more bonuses.

Upgrade structure

The Gameforge-hosted Metin2 Wiki lists six classes: Rough, Cut, Rare, Antique, Legendary and Mythic. It lists five clarity grades: Matt, Clear, Flawless, Brilliant and Excellent.

Stone levels range from +1 to +6, but the maximum depends on clarity:

• Matt through Flawless: +4
• Brilliant: +5
• Excellent: +6

For class and clarity refinement:

• Each attempt requires two stones at the current class or clarity.
• Success produces the next class or clarity.
• Failure returns one stone at the current class or clarity.

Level refinement uses one Dragon Stone and a Green, Blue or Pink Dragon Bean. Failure can leave the stone's level unchanged or reduce it by one.

What to upgrade first

Gameforge's beginner recommendation is to prioritize class before investing heavily in purity or level. The guide explains that class determines how many bonuses a stone can have, while purity and level increase bonus strength or effect.

Expected cost for class or clarity refinement

The following model applies only when:

• Each attempt follows the documented two-stone recipe.
• A failure returns one compatible current-stage stone.
• Attempts are independent and have a constant success probability.
• Compatible current-stage stones are each valued at the same amount.

Let:

• C be the cost or value of one compatible current-stage stone.
• p be the success probability for each attempt, expressed as a decimal greater than zero.
• F be the fee for each attempt.

For independent attempts with constant success probability p, the expected number of attempts until the first success is 1/p. The expected number of failures is therefore (1-p)/p.

The successful attempt consumes two stones. Each preceding failure consumes one net stone because one of the two stones is returned. Expected stone consumption is consequently:

2 + (1-p)/p = 1 + 1/p

The expected total cost is:

Expected cost = C × (1 + 1/p) + F/p

This is a long-run average under the stated assumptions, not a guarantee or spending limit for one refinement. It cannot produce a numerical estimate unless the applicable success probability, stone value and fee are known.

Do not apply this formula to level refinement. Level-refinement failures have different outcomes and can reduce the stone's level.

Editorial reference: TOG-EDITORIAL-203