Iron Mine

Primary iron production field. Produces iron every hour, and more of it at every level.

• Raise your Iron Mines to around level 8, then push one Iron Mine to level 10 to unlock the Iron Foundry.
• Then take the Iron Foundry to about level 4 before continuing the fields.
• A village does not have to be balanced. Four of each is ordinary, but a five-Iron Mine village exists and is worth settling for when the army you are planning eats iron faster than anything else - a hammer of heavy cavalry will drink it. Judge that by what the army costs, not by which tribe you are.
• Nearby iron oases make such a spot better still: they multiply what the fields already make, so the two compound rather than add.
• Getting to level 10 across the four Iron Mines costs about 67,595 resources in all.

The level nobody builds. The game publishes a level 23 and nobody can reach it: one level costs about 20 million resources, far past what any warehouse will hold, so the figures exist and the build does not. 22 is the real ceiling, and only in a capital - everywhere else a field stops at 10, or 12 in a city.

Cost. Iron is the expensive one. Taking the mines to level 10 costs roughly 5,000 more than the same levels of Woodcutters, Clay Pits or Croplands - about 8% - for the same production. Worth knowing when deciding which fields to raise first.