This is my game lol. I'm playing as Venice and I have only a few strategic territories, but the entire world is in my trade league. I currently own 16 of 26 CoTs. Some objectives you can set for yourself:
1.) Become Trade Leader in all good types (its in the trade good price page of the ledger). You also get a 5% trade income bonus for each type of good you have dominance in.
2.) Control 33% of all good types (again, it's in the ledger). You'll get all those yummy bonuses.
3.) Own all the CoTs in the world.
4.) Have all countries of any significant size in your League.
MECHANICS:
1.) Any provinces that are in your League count towards the "60% merchant compete chance for owned provinces" advantage for going full Mercantilism. This is the source of your league power. So all you need to do is conquer a CoT and bind the surrounding countries in your league, and you will have a monopoly over trade in that CoT. Unlike non-merchant republics using full mercantilism, you don't need to conquer anything else or "blob" as they say.
Edit: In 5.2 beta, the merchant compete chance for owned provinces seems to have been increased to 120%. If this is indeed the case, the grip of mercantile merchant republics on trade will probably be even more devastatingly powerful.
2.) Yes, CoTs will pop up randomly for I believe every 35 (?) provinces PER continent. Its irritating, but the way to go is either to conquer that CoT, or if it pops up some remote area, just let it die. CoTs will die when their Stagnation value reaches 50. Stagnation value is a function of three factors: Time, number of merchants, and most importantly, the value of trade. Cots with values over 300 will likely be stable.
3.) Colonize and control provinces that have base tax values 4 or higher, since only those can have Trade Stations (which are awesome).
4.) Whether a country will remain in your league or not is a function of your relations with that country, how far away it is from your nearest CoT, culture/religion, size, wealth, and whether they own a CoT of their own. To break it down more:
- If you're playing Christian, Muslim countries will almost never join your league willingly no matter how good your relations. Hindu and East-Asian countries are easier for some reason. However, if you declare war on them, force them into your league in a peace deal. Normally they will break their league as soon as the 5 years is up, UNLESS you improve your relations with gifts above 0 before then. So the way to go with most non-Christian countries is to declare war, force into your league, improve relations to 0, and chances are they will stay in your league until the next war or the reason below.
- Countries will almost always leave your league as soon as they accumilate 500 ducats in cash. This is most likely to happen in January. This means that if you see a country with whom you have good relations break off from your league in January, it probably means its a good time to attack them because they got cash. And you got the casus belli to do it
. If you leave them be, they may also form their own CoT which is really really bad. Some exceptions may also apply, as I've seen England with 800 cash but still in my league, though that may be because it won't break a league if it's at war - and England in my game is almost always at war. Oh yeah, and a good time to invite a country that's broken your league because of wealth back into a league is when it goes to war, since wars usually reduce their cash supply.
-Countries with their own CoT won't join your league except in a peace deal, but even then they won't stay. Best thing is either to conquer their CoT or starve their CoT to death (a good tactic for Lisboa).
5.) Merchant republics are limited by the minimum centralization slider of 0, and plutocratcy value of 1. They also only give 0.4 magistrates per year. Means you never have enough diplomats or magistrates. Lots of spies though. Build the Guild of St. Luke to compensate for magistrates. Also thinking of acquiring Bill of Rights NI to move the centralization slider beyond the minimum. For diplomats, explode your spheres of influence and always have an embassy. Merchant Republics also take a fairly long time to move sliders, but since you'll be staying fairly small its probably compensates. Merchant Republics also give a 33% reduction in merchant placement cost, so sending merchants is dirt cheap.
6.) I believe you get a diplomatic bonus with members in your league. 1.2 per year improvement in relations.
7.) Trade rights is mostly useless and bugged and should be ignored except for very specific situations.
SPECIFIC ISSUES:
1.) You're going to have bits of pieces of land scattered all over the globe. Means you got to scatter your army somewhat. You're also going to be in everyone's business, making alliances hard. Everyone views you as a threat.
2.) Naval supremacy is key, especially transports to move your troops around the globe. Colonize islands.
3.) Tech superiority will be easy, since you only own land of high value. CoTs give buckets of income.
4.) Making countries join your trade league takes diplomats. Lots and lots of diplomats. Max our your diplomats asap as they're the limiting factor in all you do.
5.) You should acquire the House of Trade, Importation Act, Navigation Act, East India Company, Sound Toll, Bosphorous Sound, and East India Trade Route modifiers.
6.) Certain OPMs are a nuisance and will at various times out compete you in your CoTs. Holland, Navarre, Ulm, Mecklenburg come to mind. Since I'm some 20 years ahead in tech, I've decided I can afford to embargo a few of them despite the trade-tech hit, since it effective kills these free-trading bastards once you own most of the world's CoTs.
7.) Owning so many CoTs means you will get tons of merchants (0.5 per CoT), tons of colonists (0.1 per coastal CoT), and a significant amount of Harbor Fees.
8.) Placing merchants costs 0.05 in compete chance per placed merchants. Something to keep in mind.
9.) You won't be able to compete in CoTs you don't own as a consequence of the penalty in foreign compete chance from owning uncored CoTs. Don't even try.
10.) Currently it seems that you will lose your trade league members when you change your nation tag (forming a new nation).
UPDATE:
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I was wrong: A relationship of slightly above 0 isn't always sufficient to maintain islamic countries, even after being forced into your league by a peace deal. Closer to 200 is better, but even so, it's not a guarantee. Not sure why Islamic countries are so difficult, I have no problem with Confucian, buddhist or hindu. Also, the diplomatic ability of it's ruler seems to be a factor.
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I was right: A country that is at war won't break it's trade league. EVER. It doesn't matter how much cash it's got, or how many CoTs it has inside its borders - It won't break from your league AS LONG AS ITS AT WAR. As soon as the war is over, of course, it'll break it. However certain countries are inclined to be at war indefinitely - case in point: whoever forms Russia will spend most of the game at war with a Horde. In my game Moscovy had 3 CoTs, and thousands of ducats, but it never broke from my league until it was finally at peace... at which point I attacked it and released the hordes and forced it back in my league (bwahahaha). England in my game was in one war after another, and though it broke from my league whenever it was at peace, the duration of peace was so short and the wars so long, it made inviting them back into my league worthwhile.
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Trade Rights: When you are the only Merchant Republic left, Trade Rights may be useful in helping to kill enemy CoTs when Trade Leagues won't. While provinces in your Trade League are very likely to trade in your CoTs, provinces in which you have acquired trade rights over are -guaranteed- to trade in your league. Good example is when there is a valuable Wine province next to a rival CoT. It will likely trade in the rival CoT even if it's in your league. But it won't if you have wine trade rights. Interestingly enough, countries don't necessarily break trade rights with you even if it's at war with you. In fact, I'm not sure what makes a country break it's trade rights - it seems totally random.
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Embargoes: Not as good as I originally thought. Along with a -5 trade tech penalty per country you embargo, you also lose a wopping 5 trade efficiency. They can however be used to help starve out foreign CoTs.
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The Reformation: Incredibly destructive to the League system. Once it hits, you'll be losing member left and right until it settles down and you rebuild your relations. Reformed also gets a +10% trade efficiency, making them deadly competition. Consider force-converting all Reformed nations if you're not yourself Reformed.
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Prestige: Keep it high. It helps with your merchant compete chance, though the mathematics isn't clear to me. I just know that every time my prestige dips, I start losing merchants.
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Random CoT Spawns: Since CoTs can't spawn in countries in your league, things get interesting when most of the world is in your league. I had 8 province Khiva in the deserts of Afghanistan end up with three CoTs because Khiva was one of the few countries not in my league.
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Spies: "Weaken rival league" is a unique ability of merchant republics. It reduces the relationship of a country with it's league leader by 30. It can be useful even when you're the only merchant republic left, since it works on members in your own league too. Instead of using valuable diplomats to send insults so I can declare war on members I have too good a relations with, I now send spies since I usually have tons. And, if your spy gets discovered, it's even better since your relationship goes down even more.
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Hordes: There's an exploit where you can force Hordes into your league in a peace deal. However, no diplomatic option exists to leave the league. Not even you, as the trade league leader, can kick them out of your league. So Hordes will stay in your league forever and ever. To a lesser extent this exploit also applies to Japan/Kyoto because of the Daimyo system.
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Vassals: Vassals won't break from your league so long as they stay your vassals. Criteria for league maintenance such as distance, wealth, relations, can all be ignored.
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Missions: You will get a recurring mission to have a total of 5 trade rights agreements every time you have less than 5 trade rights. This mission is frequent, relatively easy to complete, and incredibly powerful. For 5 (or is it 10?) years you get the "Booming Economy" modifier, which gives you 0.25 merchants, 3.0 prestige, and whopping 30% Trade Income modifier! As far as I am aware, this is the single biggest Trade Income modifier in the entire game and while it's in effect you will doubtlessly find yourself with a sudden surplus in income.
Europe in Trade Mapmode Before:
(What a mess!)
Europe After:
[video=youtube;Yt3D4MVGCBk]http://www.youtube.com/watch?v=Yt3D4MVGCBk&hd=1[/video]
[video=youtube;-KbjUQf-V3I]http://www.youtube.com/watch?v=-KbjUQf-V3I&hd=1[/video]