“Enhances Iron Output at Ironworks”
| Level | Requirements | Bread | Wood | Stone | Iron | Gold | Upgrade Time | Power | Bonus |
|---|---|---|---|---|---|---|---|---|---|
| 1 | Academy Lv. 20, Bread Output IV Lv. 1, Stone Output III Lv. 1, Wood Output IV Lv. 1 | 430,000 | 430,000 | 86,000 | 21,000 | 4,800 | 01:40:00 | 1,820 | +7.00% Iron Output |
| 2 | Academy Lv. 21, Iron Output III Lv. 1 | 600,000 | 600,000 | 120,000 | 30,000 | 6,700 | 02:30:00 | 1,690 | +6.50% Iron Output |
| 3 | Academy Lv. 22 Iron Output III Lv. 2 | 1,200,000 | 1,200,000 | 250,000 | 64,000 | 14,000 | 06:40:00 | 2,340 | +9.00% Iron Output |