how do you think add this?
if doing right passage and open border,
than get tech bouns,
it will be more great realistic
Open Borders Tech Trading 0.81
Open Borders tech trading for Civ4: BtS 3.03. When researching a tech that another civilization one has open borders with already has, that research gets a boost.
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if doing right passage and open border,
than get tech bouns,
it will be more great realistic