Strike the supreme treasure, drop to the next floor
Every 5th floor is a "rare vault" with double rewards. A floor ends the instant you strike its supreme treasure, and you drop straight to the next.
The supreme treasure's weight rises as you dig: 2 → 5 (dig 7) → 10 (dig 13) → 20 (dig 19), resetting each floor. Even with no luck, it is guaranteed at dig 14 (normal) or dig 22 (rare).
Hit rate per dig, pickaxes per floor
The chance of striking the supreme treasure on one dig is weight ÷ (weight + total weight of all other rewards). That other-reward total reads as R = 240 from the in-game odds screen. Summed up, the expected digs per floor are:
This matches the article's observed range of 1,330–1,440. The small gap comes mainly from how rare floors are modeled (an estimate).
320 pickaxes before you pay a yen
Of the ~1,420 needed, only ~1,080 come from purchases. The rest is free claims and in-run rebates.
Pickaxes carry over to the next event, so buying a little extra is never wasted.
No bulk discount — small packs win
| Pack | Pickaxes | ¥ / pick | Role |
|---|---|---|---|
| ¥800 | 16 | 50.0 | Cheapest — buy daily |
| ¥1,600 | 28 | 57.1 | 2nd — buy daily |
| ¥15,800 | 240 | 65.8 | Bulk workhorse |
| ¥3,200 | 48 | 66.7 | Fine top-up |
| ¥8,000 | 120 | 66.7 | Skip |
Buy in order: 800 → 1600 → 15800 (bulk) → 3200 (top-up). The ¥8,000 pack costs more per pick than ¥15,800 and is coarser than ¥3,200, so it never enters the cheapest build.
A 5-day plan to reach Floor 100
Collect the cheap core (free + 800 + 1600) every day, and place the ¥15,800 pack on the first three days to keep a progress buffer. "Floor" is the expected reach after each day.
| Day | Free | ¥800 | ¥1,600 | ¥15,800 | ¥3,200 | Day | Cum. pcs | Day ¥ | Cum. ¥ | Floor |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 26 | 16 | 28 | 240 | 48 | 358 | 358 | 21,400 | 21,400 | ~30 |
| 2 | 26 | 16 | 28 | 240 | — | 310 | 668 | 18,200 | 39,600 | ~55 |
| 3 | 26 | 16 | 28 | 240 | 48 | 358 | 1,026 | 21,400 | 61,000 | ~85 |
| 4 | 26 | 16 | 28 | — | 48 | 118 | 1,144 | 5,600 | 66,600 | ~95 |
| 5 | 26 | 16 | 28 | — | — | 70 | 1,214 | 2,400 | 69,000 | ~100 |
| Total | 130 | 80 | 140 | 720 | 144 | — | 1,214 | — | 69,000 | ~100 |
Purchased 1,084 + free 130 + rebate 190 = 1,404 effective (need ≈1,400). A 5-day event: collect the cheap core daily and front-load the ¥15,800 packs to keep a progress buffer.
If unlucky: you should reach about Floor 95 by the end of Day 4 and clear 100 on Day 5, but that sits right at the expected line. To be safe against bad luck, add one ¥3,200 on Day 5 (about ¥72,000, ~103 floors). To fully cover the worst case (1,560 picks), add one ¥15,800 and budget about ¥85,000.
Blitzing costs about ¥9,000 more
The cheap core resets daily, so the fewer days you use, the more cheap slots you forfeit. Spreading across all days is cheapest.
One day of maximum buying (958 picks) reaches about Floor 79. Floor 100 is roughly 1.3–1.5 days of that pace.
50 Mithril + 100 picks + ~2,900 gear chests
Floor 100 grants 50 Mithril. On top of that, the reward you pick as each floor's prize, 100 times over. Gear chests drop at 24 per floor (48 on rare floors), for about 2,900 across 100 floors (2,880 in theory, 2,923 measured).
Similar total cost — choose by contents
A full 100-floor Treasure Hunter run (~¥67,000) and a full Aurora Hop (~¥59,000–62,000) sit in the same price band (a ~$400 tier — likely by design; this is an estimate). At equal cost, pick by what you need.
Treasure Hunter wins
- Gear-chest volume (~2,900, ¥24 each)
- A fixed, guaranteed 50 Mithril
- Fast, hands-off auto-digging
Aurora Hop wins
- Mithril cost (¥600–700 each, up to 70)
- Gem blueprints and jewel materials
- Strong free / diamond path
The rule: run whichever solves your current bottleneck. Short on gear → Treasure Hunter. Short on Mithril or jewels → Aurora Hop. Running only the side you need, up to its efficient point, beats maxing both.