screwtype said:
Hm - what techs no one else had could Japan offer at this time ?
AFAIK they learnt those new technology pretty quickly by sending students to european and american university and back at home they used and spread those new knowledge .
Japan wouldn´t have to give techs, but rather trade concessions (which can be seen as gold or gold/turn)
I think the borders between science points due to trade with another civ which already has a tech and tech trade are very fluid.
For example I would see the japanese teppo as a result of tech trade. The portugese didn´t give the japanese the tech gunpowder directly, but they gave them muskets thereby allowing the japanese to study them and therefore unlock the science (at least I would think that this is the best description which could be given in Civ IV terms).
Maybe allowing students of some other country into your universities could also be seen as tech trade (given the right period of time).
You give us gold and we allow your students into our universities and therefore enable them to unlock one of our techs which we have but you don´t possess.
After all I don´t know of one RL example of direct tech trade where one country directly gave another country a tech (for example by giving them all blueprints for a certain weapon it didn´t have and scientist which would help this country to build his own manufacturing plants for this weapon)