Thank you for replying!
True, it isn't among the toughest achievements, but it does pose some serious challenges. I don't consider myself a great EU player - usually i have a long idle period no matter how genius and great things i do sometimes. Well, if that's the case i really hope my post helped you and that you'll get them
Well. I can roughly say some of the things i planned/did and why i did it. Maybe it's not the best way to go but it can wield some useful information.
^The most important move IMO, is the first move - annex Kai (and preferably Rikuzen)
I started off as Uesugi because it's one of the largest daimyos, that's sitting in a place in Japan that i find most comfortable. Also, it borders a one province minor Takeda, that owns a gold mine in Kai, which is
vital to get your economy to manage-able levels. Also, Uesugi has a core on
Musashi, so a
rightful ownership event may give you this fortified, high development province. Out of all countries on the island Japan has the most difficult economic situation due to their very low income and massive army. In the beginning they will have around 20k, but only in a few years (after a war or two) that number will dwindle to around 14k - and lower. If you play as Uesugi, destroy or sell all your ships right off the start. You won't need them anytime soon, but you will need those extra 30 cents. When you become Japan, this becomes an entirely different story - it's crucial for Japan to build a dominant navy. It's a game saver.
I didn't put a national focus in the first several years since Noritada Uesugi is the best ruler out of all others in Japan (4/4/4). In the first few decades, it's tough to hire more advisors and amount a satisfactory number of ducats for development and extra spending. Milk estates early in the game to get monarch points and a good general. The fun thing with Daimyos is that they get tons of army tradition, so even when you get a bad general, you have a good shot at getting a good one because of your supposed high army tradition (seriously, mine hung around 20-50 for most of the time at least).
My first idea was Exploration (this might have been a slight miss, as i couldn't fund building colonies and run other affairs effectively early on), but this idea will be an important one, especially when you unite Japan. Colonizing the Pacific (and potentially going for the Americas) is quite fun. Japan is the end of the world for the first few institutions, so you will spend huge amounts of monarch power for teching up - although you will be able to keep up for a few decades once the institutions start. My second idea was Expansion, and third Offensive, which bodes pretty well with the Japanese offensive units. Be economic with your ideas, though. You need to reap all benefits of no institution penalties in early game. Other ideas to consider: Religious, Diplomatic, Trade.
- I think the key is in the beginning - try to get one where Kai and Date would ally so you could beat them both in a single war. Try to ally 1) Hosokawa (if not, rival) 2) Shimazu 3) Ouchi 4 (Nanbu).
- Be wary of the economy during war - Daimyo loans are so small (7 or 9 ducats) that just a few defeats and attrition/over the force limit/reinforcement setbacks can bring your economy to the knees in a matter of minutes.
- Capture Kai early. Ideally this is your first expansion. Kai gold mines will be your economic backbone for the rest of the game. Increase production by one as soon as you core it. Don't give it to any institution. Ideally, if you take Kai and Rikuzen, you can use Hitachi and Rikuzen as estate provinces since they don't have huge development. Don't let Nobility take over your country in any way. You lose Daimyo rank, along with it a +10% army morale boost. War for the Emperor is the way to go eventually.
- If you own Kai and Rikuzen and don't have tons of loans at this point, you could potentially look for an advisor (preferably one that reduces inflation, or a military one). If a Rightful Ownership of Musashi triggers, always ask for it. If Japan declines you once, it's a bummer, but don't worry too much, the event will trigger again (I think they always accept at some point. I was lucky that they accepted 1st time though).
- One thing i noticed - Indonesia region was the first region that embraced renaissance in the vicinity. You can try to colonise adjacent islands to push for renaissance more).
- Once you get 4-5-6 provinces (or say once you get over 12k maximum force limit), other Daimyos will be very disinterested in bringing you down, even with their allies, so look to ally only a few, smaller Daimyos that won't regularly cause you trouble with Japan. If Japan failed to annex some Daimyos in the first few decades, this is a great thing, as the Daimyos liberty desire will sky rocket, and they won't help Japan in independence wars (they will just stick by their provinces and won't even attack you if you fight on Japan's side). You will easily beat any independence coalition with Japan at your side anyways. If everything goes according to plan, Japan will be in a very rusty spot around 1460-70's and then you could seriously prep up for bringing them down. Once the last independence war ends (preferably you will be fighting by Japan's side), look up if you have a truce on Japan or you can actually declare on them. If you can, look up for all other daimyos will to ally with you. When the time is right, ally as much as you can and declare on Japan (they will even have mothballed forts in some cases). This is ought to bring them down if you're used to the warfare in Japan. Note, to become emperor of Japan, you need to fully annex all of Japan in a single war.
- Once you're Japan, the daimyos you were in war with will be your Daimyos now, and the Daimyos that were your allies still be daimyos, but independent. It looks very weird but don't get too confused. They won't ally anyone. If you no CB on them, your daimyos will help you and you will get half of the remaining daimyos relatively quickly. The daimyos that are still your vassals should be an easy work if they don't have 4-5-6 provinces. This really slows down annexation time - i had this exact problem in my playthrough, Ouchi became too big for me, but i managed to Annex them in a few decades.
- When you're done with internal struggles, go for Hokkaido and annex Ainu, colonize the Kurils (required for achievement) and look for further expansion. Don't worry about Korea. Keep good relations with Ming - they won't attack you. If they ally you, it only helps with Korea.
- Use your big naval force limit to your advantage. Pick ideas that boost your naval force limit. Build a dominant pacific fleet. Build 5 Carracks (Draft ships for war - Merchants' Guild), and a ton of light ships. Don't buy galleys.
- As a fully annexed Japan, you will ideally need around 25k regular army, which will be around your force limit once you control most of all of Japan (it is higher, but you wont need more than 25k). Build close to, if not, as many transport ships. Figuring out how to logistically run your armies, transports fleets and battle fleets will be key for most of your game time.
- Korea can be very easily beat with a good navy. Your navy should be superior.
- Try to take out Korea entirely at some point (or make them your Vassal, take Jeju and some other provinces). Don't convert Jeju to Shinto. Shinto faith is a bitch to convert (-2 missionary strength modifier) and it will be very hard to convert it later on without Korean as an accepted culture (Shinto faith, unaccepted culture and western trade modifier make it nearly impossible to convert a province). So, if you're going for Kirishitan, think ahead a lot. Shinto provinces will be the toughest to convert!
- At some point in early-mid 16th century, you will get a few events linked with Europeans. There is an event in which you are asked to help a Portuguese or a Dutch shipwrecked monk, who would in turn convert one of your provinces to Catholic. Now, this was key. Accept it. This way you welcome catholic zealots in Japan. When they spawn at some point, let them do as much as they can. If you're on max army force limit, you'll be just fine (there were no more than 12k in my playthrough). These guys took some time (i sporadically reconquered provinces they would convert, not to lose precious province moneyz, so they would often return and conquer it back blah blah), but be patient with them, as you likely won't trigger them all that much in the game. You can only convert once they enforce their demands on you (be ready for a moderate prestige hit) and you accept it. But you can do it without them controlling all your provinces, but the requirement is that the dominant faith in Japan is catholic. If you didn't somehow manage to magically expand too much at some point, you will have no trouble with this once they convert most of Japanese island, because if you have colonies, many of them will likely be animist, some even muslim, so they only help your cause. Once you accept rebels' demands you will without a doubt have a lot converting to do. I enforced like 5 acts that increased my missionary strength but they weren't enough to convert my largest remaining provinces, and Jeju, which had an unaccepted Korean culture and Shinto faith (that conversion was my big mistake). If you see no way, get the requirements that enforce Sakoku Law, which nullifies Western Trade modifier, which is highly valuable, but i had no other option in my playthrough.
That's about all i can say. I think taking Religious ideas are great for Japan, but i don't think they help as a first idea. Maybe fourth or third. I'm not sure.
Have fun and good luck!
