Jewel of Soul: complete guide to upgrading +7 to +9 in MU Online

The Jewel of Soul is where MU Online's upgrade system becomes genuinely risky. You've safely upgraded to +6 with JoB. Now you want +7, +8, or +9 — and every attempt has a real chance to fail and lose your work. This guide covers the full mechanics, risk assessment, and strategy for upgrading beyond +6.

What Jewel of Soul does

Mechanical function:

How it works:
1. Right-click Jewel of Soul in inventory
2. Click the item to upgrade
3. Animation plays → result: success or failure

On success:
→ Item gains +1 upgrade level (e.g., +6 → +7)
→ Item is now at the new level

On failure:
→ Item penalty applies (server-dependent — see below)
→ JoS is consumed regardless

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Upgrade range (JoS only):

+6 → +7: JoS (failure risk)
+7 → +8: JoS (failure risk)
+8 → +9: JoS (failure risk — highest)
+9: maximum upgrade level (Excellent items cap at +9)

Note: +10/+11/+13 exist on some servers via special materials
These are server-specific and NOT standard S6 mechanics

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Success rates (approximate for standard S6):

Level          | Success rate  | Failure rate
---------------|---------------|--------------
+6 → +7        | ~75%          | ~25%
+7 → +8        | ~65%          | ~35%
+8 → +9        | ~55%          | ~45%

Important notes:
→ These rates VARY by server configuration
→ Some servers have 80%/70%/60% (generous rates)
→ Some have 70%/60%/50% (punishing rates)
→ Always check your server's rates before attempting

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Failure consequences:

The two most common server behaviors:

Type A (most common): fails to +0
→ Item survives but loses ALL upgrade levels
→ Example: fail at +9 attempt → item drops to +0
→ Loss: all the JoS invested in previous levels (need to redo)
→ The item itself is preserved — no permanent loss

Type B (less common, more punishing): item destruction
→ Item is completely destroyed on failure
→ Loss: the item itself + all invested JoS
→ Very high stakes — NEVER attempt with only one copy

Type C (some servers): fails back one level
→ +9 attempt fails → item drops to +8 (not +0)
→ Less punishing — just loses the most recent level
→ This is the most player-friendly failure mode

Check which type your server uses BEFORE any +7+ attempt.

Success rate improvement

The "+0 additional option" technique:

How it works:
On many S6 configurations:
→ Upgrading with the item's additional option at +0 (unleveled)
→ Gives a higher success rate than upgrading with leveled option

Standard approach:
1. Get your item to +6 (JoB only, option at +0 is fine here)
2. Use JoS to upgrade to +7, +8, +9 BEFORE adding option with JoL
3. Once at +9: THEN add Jewel of Life for option levels
4. Result: higher JoS success rate during the risky phase

Why this works:
→ The item's additional option level is a second multiplier in the formula
→ Option at +0 simplifies the calculation → better base rate
→ Option at +28 (max) + JoS: slightly lower rate (more complex formula)

Practical impact:
→ Difference is small (maybe +5-10% better rate) but meaningful over many attempts
→ Standard advice: "upgrade level first, option later"

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Happy Hour:

Many servers run "Happy Hour" periods:
→ Time windows where upgrade rates are boosted
→ Typically: +5-15% to success rates
→ Check server website/Discord for Happy Hour schedule

Strategy:
→ Save your high-risk +9 attempts for Happy Hour
→ A single successful Happy Hour session can save 5-10 wasted JoS

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Lucky variants (server-specific):

Some servers have:
→ "Lucky JoS" or "Blessed JoS": guaranteed success (rare)
→ "Upgrade protection": item doesn't drop if failure occurs
→ "Combo upgrade": multiple JoS in one attempt with rate boost

These are NOT standard S6 mechanics — check your server's custom features

Economic cost of failed attempts

Understanding the JoS investment:

To upgrade one item from +6 to +9 (optimistic scenario, no failures):
→ 1 JoS for +7
→ 1 JoS for +8
→ 1 JoS for +9
→ Total: 3 JoS

Expected attempts accounting for failure rates (~70%/65%/55%):

For +7 (75% rate):
→ Expected attempts: 1.33 on average
→ Cost: ~1.33 JoS

For +8 (65% rate):
→ Expected attempts: 1.54 on average
→ Cost: ~1.54 JoS

For +9 (55% rate):
→ Expected attempts: 1.82 on average
→ Cost: ~1.82 JoS

BUT: on Type A servers (fail to +0), each failure at +8 requires re-doing +7
And each failure at +9 requires re-doing +7 AND +8

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Total expected cost on Type A server (fail to +0):

The math compounds:
→ +9 fails: need to redo +7 (1.33 JoS) + +8 (1.54 JoS) + retry +9 (1.82 JoS)
→ Expected total JoS for +9 on Type A server: ~5-10 JoS
→ "Unlucky" scenarios: 15-20+ JoS for one +9 item

Price implication:
→ 1 JoS ≈ 1 JoB in most markets
→ A +9 item that required 10 JoS to reach = buyer expects to pay 10 JoB premium
→ This is why +9 items cost significantly more than +6 + the upgrade cost

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Price example (Excellent Sword):

Base excellent sword +0: 5 JoB
At +6 (6 JoB added): value ~11 JoB (5 base + 6 JoB cost)
At +9 (average 8 JoS added): value ~23 JoB (5 + 6 + 12 expected JoS cost)

Why +9 costs more than the sum:
→ The RISK premium: seller lost multiple JoS attempts on the way to +9
→ Buyers pay for the success AND the risk the seller took
→ A +9 item with great options: the risk premium can be very high

When to attempt +7/+8/+9

When you should attempt upgrading:

Safe scenarios:
1. You have 5-10x more JoS than you think you'll need
2. You have access to an equivalent replacement item if it fails to +0
3. You're not in active PvP events (don't upgrade mid-CS)
4. Happy Hour is active or upcoming

Risky scenarios to AVOID:
1. Only one copy of the item + Type A/B server = do NOT upgrade
2. You have exactly the right JoS for 3 attempts (need buffer)
3. Emotionally invested in specific outcome (leads to bad decisions)
4. Server has high failure consequences with no protection

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The "one item upgrade" discipline:

Common mistake:
→ Upgrade multiple items simultaneously
→ Multiple failures simultaneously = catastrophic loss

Better approach:
→ Finish upgrading ONE item completely (+9) before starting next
→ One success before next risk
→ Psychologically manageable: you see progress

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When to stop and sell at +6:

Sometimes +6 is the right call:
→ If your server has very punishing +9 failure rates
→ If you need the JoB more than you need the item upgrade
→ If the item isn't critical enough to risk the investment

The calculation:
→ Item at +6 worth 20 JoB
→ Expected cost to reach +9: 8 JoS (8 JoB equivalent)
→ Item at +9 worth 35 JoB
→ Profit from upgrading: 35 - 20 - 8 = +7 JoB
→ If this math is positive: upgrade. If negative: sell at +6 and buy +9 from market.

See also the Jewel of Bless guide (the safe +1 to +6 path), the Jewel of Life guide (adding additional option levels), and the item economy guide (understanding +9 item prices and when to buy vs upgrade yourself).

Frequently asked questions