Spies ... the Chinese used them quite often to gather information at other cities or sabotage something. In Emperor, you'll be able to send spies to other cities, but you'll also have to watch out for spies from other cities who are there to sabotage something in YOUR city.
Usually you can either send spies gathering information and spies conducting sabotage. However, in some missions, sabotaging isn't allowed. If you're playing multiplayer, spies will work a little differently than when you're playing single player, so I'll explain both sides... but not yet. I don't have enough information on spies in MP yet to write something about it, so that's "coming soon".
Gather information: the spy will go to the other city and inform you of major events, like giving very early warnings when the other city wants to invade you. This way you'll have a much longer time to prepare you defenses.
Sabotage Military: this is probably the most effective spy: it will destroy much of the city's military: a 5-shield city can go down to a 1-shield city in just a couple of months, which makes it very easy to conquer them.
Sabotage Industry: will increase the number of goods the city is willing to buy: you will be able to sell 12 loads more per year to the city. The good is randomly chosen from the goods the city buys.
Sabotage Housing: according to the manual (page 73) "can increase the maximum price it will pay for some trade items" (I haven't investigated this yet, any comments welcome)
Sabotage Food supply: according to the manual: "can increase the amount of foods it is willing to buy"
Spies in your city
Just as you can send spies, others can send spies too. Spies will not enter your city like immigrants do, but they are 'teleported' to one or another building and appear out of that building later, disguised as the 'normal' walker of that building.
Possible disguises a spy can take: herbalist, acupuncturist, inspector, guard, water carrier, announcer, daoist priest, buddhist monk, diviner, tax collector. This list isn't complete: these are only the disguises I have seen so far. (additions are welcome)
Those spies aren't in your city for nothing: they will eventually do something that won't benefit you. When a spy comes out of a building, he walks (via roads if possible) to his 'target' building. Once he gets there without being caught or disrupted, he'll spin around in front of the building for a few seconds and then do his damage. That can be one of the following:
- Steal all raw materials from an industry building
- Steal all weapons/wood from a fort
- Steal all food and goods from a house, often elite housing
- Steal goods from trade buildings
- Some people reported collapsing Administrative Cities and Palaces, possibly caused by spies
(Again, this list isn't complete, additions welcome)
If you right-click on a spy, he admit that he's a spy, and will disappear instantly. You haven't eleminated from the city, however: he just goes into hiding and will try again at the start of next month.
Spies can only be caught in two ways:
- a guard from a watchtower sees through the disguise of the spy and catches or reverses him when he passes the spy.
- Sun Tzu walks into a spy and reverses him.
The chance that a spy is caught when a guard walks past him isn't 100% however. You might see a couple of guards passing a spy without recognizing him.
When a spy is discovered by your guards, they either 'catch' him or reverse him. If they catch him, the spy gives you 800 cash and promises to never bother you again, and is let go free. If a spy is reversed, however, he will, at your command, return to the city where he came from and spy there for you. This requires some action from your side: if you get the message that a spy is reversed, remember the city where he came from, go directly to the empire map and send a spy to that city. This spy won't cost you any money. If you don't send a spy right away, you missed the opportunity to get a free spy.
Tips for catching spies
- Put watchtowers in all important areas, like industry, housing, military, and let guards patrol choke points like bridges where a spy is likely to pass.
- However, too many watchtowers will lower your popularity: do you want to live in a city with cops passing your house every 5 minutes? As a rule of thumb, try to have one watchtower for every 500 people in the city.
- Upgrade your watchtowers: that way you'll get 2 guards on the streets for the price of one.
Myths about catching spies
When I right-click a spy, I caught him and he won't return.
Wrong. You just forced him into hiding. Next month he will be out on the streets again, looking for targets.
My city is entirely surrounded by walls and one gate, every spy has to
pass through that one gate to enter, so I'll just see them walking into my
Wrong. Spies don't enter you city by just walking from the entrance point of the map to your city, they just appear inside some building (for example an herbalist's stall) and come out of that building later, disguised as the normal walker that belongs to that building (in the example the spy will be an herbalist).
My gate will stop the spies from going through.
Wrong. Gates don't do anything to stop spies, they are disguised, remember? If you were a guard in that gate, would you ask EVERYONE to show their real identity if they wanted to pass?