I used that ultra-cool guide for japan and got a mighty empire, but beware of expanding way too much. Getting korea got me into a 30+ years war with Rusia(it only ended because I left the campaing before finishing!), and they had gas and strurmtroopers like in 1880 or so! I needed 5:1 odds to win battles until I managed to catch up in military tech! which was like 20 years latter!

o
Also expanding thru SE asia set me into another war
at the same time with france. Both countries seemed to be comited to fight the glorious japanesse empire to the death and only france accepted peace after being completely defeated in the battlefield (thou I think they again DOW'ed me latter) the russians were fighting stalingrad like, no matter how many millions they could losse they wouldnt even hear about a peace settlement. France is particulary boring as they like to make landings in mainland japan(that no paradox game seems to be able to produce a warning of that so you can send garrisons to the province before the landing takes place) forcing you to constantly be distracted having to mop up.
However if you like the military aspect of vic (in vic I enjoy more the economic game and preffer short wars only to get the booty and civilize those poor barbaric hordes

) you'll love that total Asian war that will develop.
I cant confirm but I remember reading somewere that what triggers the alarms in Russia and France is Japan anexing Korea, so I dont recomend it unless you have great millitary tech, a mighty huge army and low mil so you can deal with 100% war weariness.