Bronze Polishing
Bronze Polishing is a metallurgy technology. Its listed prerequisite is Bronze Forge, and its cost is 30 red technology points.
Prerequisite and cost
Section titled “Prerequisite and cost”The technology definition lists Bronze Forge as the prerequisite and 30 red technology points as the cost.
Unlocks
Section titled “Unlocks”The unlock list contains 
Polished Bronze, 
Bronze tools and 
Copper Trinkets.