State of the Nation, 1599 to 1699
The momentum has really picked up now and Japan is looking much closer to what I envisaged it being by the end of the game. In fact I hadn't given a whole lot of thought to colonisation, but with the Chinese territories approaching the limits I had in my mind when this started I've begun to look further afield.
I don't have a lot of interest in expanding further to the west or south as those regions are full of low base-tax states that will drag down my tech rate. For that reason I've switched over to colonising the islands to the south including what presumably now won't be called the Philippines.
I had thought that this would be a good way of getting a western neighbour, but it's 1699 and so far there has only been limited interest from the Europeans. Scotland, Britain and Castille are all sniffing around though, so they're definitely coming closer.
The goal for the next century is to westernise both my tech group and the military. That seems a nice sensible aim for now.
Economy
Number of provinces: 78 (45 in 1599; 31 in 1499; 19 in 1399)
Annual Census Tax: 1167.39 (387.15 in 1599; 146.86 in 1499; 69.69 in 1399)Per province: 14.97 (8.60 in 1599; 4.74 in 1499; 3.67 in 1399)
Business is booming in Greater Japan. Getting universities and manufactories has obviously helped, as has my selective chipping away at Qin and Wu's richer provinces.
Progress hasn't been quite as rapid as in the previous century, but my colonial strategy is probably slowing me down somewhat in this regard.
Size-wise we're the major heavyweight in East Asia as you can see from the world map at the bottom of this update. We're not doing too badly overall as this international comparison shows.

Second place! Perhaps not a comfortable second, but far enough ahead of Castille to make a place in the top three a certainty. If this were Vicky 2 I'd be... well, I'd be an Unciv, but a powerful one. I've managed inflation back down to zero, unlike France, Russia and Castille who seem to be happy with it in double-digits.
Scotland and Navarre are also doing well and Britain has mostly recovered from losing London and indeed most of England to the Pope.
Austria are throwing their weight around and have broken the infamy limit, so should have their hands full and not trouble distant Japan.
Technology

Monthly investment: 275.8 (98.6 in 1599; 40.0 in 1499; 20.6 in 1399)Per province: 3.54 (2.19 in 1599; 1.29 in 1499; 1.08 in 1399)
What does a colonial power possibly need with naval technology. These carracks and cogs were good enough for three hundred years, so why change now?
This is the main reason I'm wary of war at sea - I've completely neglected the navy for the entire game. Land technology is a different story. Japan can now field cannons and Asian arquebusiers which gives the army quite an edge against our neighbours. The Europeans might be a little harder to handle however.
Per province monthly investment hasn't climbed as much relative to the 1499-1599 improvement, but represents a larger absolute increase (+1.35 as opposed to +0.90). This means that the tech rate has been accelerating even as the empire expands.
Some of this is down to much greater production efficiency and the fact that Japan can now boost tax through constables (at Gov 20). Trade has also picked up as I've begun to auto-send merchants to CoTs outside the Empire. Japan is making 40.3 ducats/month now compared to a mere 6.3 in 1599. That's more than doubled the trade contribution to the monthly budget even as the tax and production inputs have climbed.
Military
Army size: 94/148 (65/109 in 1599; 32/45 in 1499; 6/28 in 1399)Army upkeep: 33.2 ducats/month (19.1 ducats/month in 1599; 9.1 ducats/month in 1499; 1.3 ducats/month in 1399)
Manpower: 108,000 (75,922 in 1599; 33,498 in 1499; 15,274 in 1399)
Being rich has allowed me to expand the army, although there's room for further growth if necessary. Fear of a European DoW has meant I've been keeping maintenance at full. The healthy state of the economy means I can still do this and turn a handsome profit (~600 ducats a year).
Manpower is somewhat of a greater concern. It's grown, but nowhere near as fast as in previous centuries. A determined attack by a European major power could rapidly deplete Japan's reserves.
Navy size: 74/69 (68/81 in 1599; 45/52 in 1499; 37/44 in 1399)Navy upkeep: 3.8 ducats/month (3.5 ducats/month in 1599; 2.4 ducats/month in 1499; 1.5 ducats/month in 1399)
Something odd seems to have happened here. My naval forcelimits have fallen by two over the past century despite adding more provinces. Not sure what's going on there, but fortunately naval upkeep is dirt cheap so that's not a worry.
Most of the additions to the navy have been galleys for anti-pirate duties. The main fleet is still around 20 carracks and 20 cogs with a few galleys in reserve. I've no plans to go on a ship-building binge until after I can raise my naval tech to something more respectable.
Armed forces comparison: 1599

Armed forces comparison: 1699

Since Wu is reduced to three disconnected provinces and Qin isn't doing much better I thought I'd widen out the comparison this time. Japan is the premier regional power, but the armed forces don't come close to those fielded by the big European states. I'm going to increase the amount of artillery in the army in the hope that this can give Japan a decisive advantage in battle. The fact that it will always be as good as the equivalent tech-level western unit doesn't hurt either.
Japanese manpower does seem paltry, but I believe it's the result of not having a land connection between my capital and the majority of my provinces. You can see the same thing with Britain, who have moved their capital to North America. All their high-manpower states are across the Atlantic and so the number of troops they can field is drastically reduced.
Home affairs

The personal union with Lan Xang I mentioned in the last update ended up with Japan inheriting the whole country. As I said I would I immediately released it as a vassal, so that's my first dynastic win of the game.
The benefits of high prestige are also underlined here. Cheaper stability costs, higher morale and boosts to trade income and legitimacy are always nice to have. The downside of this is that I have to dedicate two of the three adviser slots to maintaining this state of affairs, but I'd say it's well worth it.
The Court

And here's where the picture begins to look a little less rosy. Neither my aging Emperor (who dies in 1701) nor his heir are anything to write home about. Nakamikado in particular has a disastrous Admin rating and neither of the pair are good enough to westernise. Westernising the military requires an Admin 8 ruler, so I'm a little worried.

In the last update Japan had two national ideas and now has five. I've added Ecumensim - which has played merry hell with the number of Shinto provinces - Colonial Ventures and QFTNW. In retrospect I should have picked the last two the other way round as I spent a long time with 5 colonists but no viable targets.
I purposely haven't been colonising Siberia as it's so poor, although that didn't stop some of my subjects deciding to set up a colony there on their own. 
The sliders show another good reason for the switch to administrative monarchy. Japan is now fully centralised, but that's only a +2 revolt risk rather than the +5 it would have been under feudalism. The Empire is also fully Free Subject, Innovative and Quality (the last of which can't have helped my manpower).
Shinto has slumped into second place in terms of religion in the empire. It doesn't matter a great deal in gameplay terms, but I'd have like to do a bit better than this. Chihan has also overtaken Japanese as the largest culture! Let's hope their conciousness stays low for a bit longer!

World affairs
And here are the world maps. Interesting to note that seventh-richest-country Navarre is apparently an OPM. Shades of Militaris' AAR there.
The usual suspects seem to be doing well too. Leader of the pack France has consolidated its holdings in the Balkans and Anatolia and has crept further into Italy.
Japan in 1699

World in 1699