A couple of questions

[caralampio]

Having finished 4 long campaigns, I have a couple of questions:
1. I have been striving to learn the whole tech tree, but I made numbers and it seems impossible within the time frame (1699). Am I right? Anyhow, is there some Steam achievement for doing it?
2. In my last game I recruited a geisha for the first time (after getting the Infamous Whatever district for the first time too). I never got to use her, or even move her, since I won the next turn. The building says that "it adds one to the number of geishas you can have". But I never found how you can have more than one geisha since there is only one infamous district. Is this correct? It seems rather useless to have a character class of which you can only have one. And she doesn't seem very useful anyway.

[Alexandru]

1. You can use Radious Technology Mod to speed up the research rate. I don't know about the achievement as I never got to research all the techs.

2. You can have only one geisha. If you look closely in the building details you'll see the "+1 number of geisha that may be fielded"-line lacks the next part: "(to a maximum of 5)". All of the other agents have that part.
And she is usefull, a better assassin than the ninja, if I remember corectly.

[Drtad]

Having finished 4 long campaigns, I have a couple of questions:
1. I have been striving to learn the whole tech tree, but I made numbers and it seems impossible within the time frame (1699). Am I right? Anyhow, is there some Steam achievement for doing it?

The vanilla campaign is designed so that you have to pick and choose what parts of the tech tree you want to focus on. It is indeed rather impossible to get all the techs within the timeframe. There are ways to speed up research-monk promotions, general promotions, library provinces, buddhist temples, and churches.

There is a steam achievement for researching the highest bushido tech and the highest chi tech. One of them is Shih and the other I can't recall right now.

2. In my last game I recruited a geisha for the first time (after getting the Infamous Whatever district for the first time too). I never got to use her, or even move her, since I won the next turn. The building says that "it adds one to the number of geishas you can have". But I never found how you can have more than one geisha since there is only one infamous district. Is this correct? It seems rather useless to have a character class of which you can only have one. And she doesn't seem very useful anyway.

Never had the chance to use one in regular S2 (common in Fots) but from what I understand she's a very effective assassin and not much else.

[Busta]

Thougt that a geishas best use is boosting economy...

[wealthmonger]

1. I have been striving to learn the whole tech tree, but I made numbers and it seems impossible within the time frame (1699). Am I right? Anyhow, is there some Steam achievement for doing it?

In an old mori long campaign I went thru the Chi side by about 1575. I didn't do anything on the bushido side. I Converted and spammed churches as quickly as possible, plus a philosophical tradition province. You have to get the Chi % rate into the 200% range.

Then I switched to building up the castles as quickly as possible for the bushido rate boost. It was somewhere in the 1580's that I finished the bushido side. I think the bushido rate was also in 200% range. This was with the maximum number of provinces possible PreRd in a long campaign.

[eXistenZ]

there are two achievements for the standard shogun II (military might and glittering grand cities)

there is one achievement for fall of the samurai, when playing as the nagoaka, for researching an 8th tier tech

[Drtad]

Thougt that a geishas best use is boosting economy...

That's in Fots, not S2.