I haven't seen this addressed anywhere and was wondering if the number of question mark resources pictured on the tech cards means anything? for example on the Philosophy card it shows 2 resource tokens and on the Pottery card it shows 3 resource tokens. Does this mean I need that many resources tokens of any kind before using that ability? Another question just came to mind, if I do have to use multiple resource tokens to use the tech abilities, do they have to be different resources or can the all be the same kind, such as 3 iron tokens as opposed to 1 iron, 1 wheat, and 1 silk?

A question mark on tech card means any resource. Two question marks mean two any resources, they may be the same, but are not required to be the same.

mikko_r said:

Correct, flip the rulebook over to the back, you'll see the "?" item there as "any resource".