Technology paths - Emperor and above

[trev]

The only way to be competitive at the highest levels is to research a tech and trade it for many others.I tend to beeline to particular techs because I have found from experience the AI does not prioritize them, and therefore they can be traded for in excess of 10 other techs sometimes. The best techs for this are techs of high beaker value.
My first choice is alphabet, so tech trading is enabled, this may not be traded immediately. At this stage Code of Laws and Ironworking can sometimes be traded for other techs.
After alphabet I usually go for Literature so I can build the GL.
My first major tech for trading is usually Paper, this can always be traded for earlier cheaper techs, often up to 10 or more of them.
The 2nd major tech is next in the tree Printing Press, even when I was to alphabet about 30 turns after the first AI, I still got to this first, and traded at least a dozen earlier techs for it.
After this point my tech trading is usually less successful, but these techs are usually good at least 2 or 3 trades, Education, Democracy, Military Tradition, Steam Engine, Assembly Line( this is one of the best for trading, but often I will hold back on trading this, and initiate or intensify wars at this time).
Late in the game Radio, Computers, Genetics, Medicine, Refrigeration are not hard to be to first, but trades are not easy to come by as the AI's will usually redlist their techs.
I was wondering if other players who follow other tech paths have suggestions for good trading techs apart from those I have mentioned.

[rah]

Astronomy is always a hot one. Gunpowder is another.

[uberfish]

Philosophy - highest value tech you can get from a single GP. Useless in AI hands. Enables liberalism which gets you more stuff to trade.

The other techs around 900-1000 value (Theology, Music, Civil service) also have high trade value if you get them early and you can trade them for the various medieval techs which have names beginning with C.

If you want to trade for late game techs, either cultivate friendly relations with a civ or refrain from trading for too many cheap early techs.

[Styx]

Could be dangerous to trade like that. You must be absolutly sure the AI has no techpath hidden for you.
For instance if the AI is on the gunpowder route, but you don't know yet, because you only see guilds but in fact he has chemistry already and if someone trades Music and Philosophy, the way to Nationalism and Militairy tradition is short.
The AI will trade it like mad among eachother.
The only correct trade is with the lower developt AI and you are sure there is no hidden research path.

[One_more_turn]

You also need to worry about diplomacy. You better get everyone to be pleased at you, otherwise, you don't get anything decent to trade.

[Blake]

I often go for Guilds-Banking-Chemistry-Steel in the mid game, basically researching straight up that path with minimal diversions, only to the odd tech like Compass for pure trade fodder.
The nice thing about the Guilds path is it gives a very awesome top-notch military and cash multiplier to pay that military. I find that being competitive in tech isn't that nessecary when all your tech is geared towards your army. In spite of that I find that Guilds is usually a very tradable tech, I usually get to Guilds 2nd or 3rd and can trade it around for quite a lot of stuff. All techs past Guilds will also be tradable, you might not get to them first (AI's with a strong military bent like them), but peacemongers tend to neglect those techs so you can trade for the peace techs. It's worth noting that the AI types who do put a high priority on military techs are also the paranoid non-trading types - unlike the likes of Mansa Musa who quickly reserches peace techs then trades them around like a whore. Beating Mansa Musa to a tech is important - it's not so important to beat Tokugawa to a tech.

A nice thing about trading military techs to the peaceful AI's is they are far less likely to use them against you, and it gives warmonger AI's less material to trade so they stay backwards.

Overall I find that basically beelining Fuedalism through Steel is pretty much sure-fire success. I always find going the peaceful liberalism route a bit of a gamble, because you're gambling on being able to trade for military techs to defend yourself, and might not get liberalism. You also have lower cash multipliers so can't emergency upgrade as easily.

[trev]

Some good ideas, gunpowder, philosophy(when i get it from a GS) I have found good for trading, the line mentioned by Blake I have never tried, ie Guilds through to Steel, sounds like an excellent idea. Only thing though I would have to do is discard the Paper, Printing Press line which also works extremely well, but I will give it a try in a game soon and see how it pans out and whether it is better.