Hi Gregoshi, refering to the website, soutenryoku is currently available on both PC (Windows98/Me/2000/XP) and PS2. It was released on 7th Feb 2003. I doubt that the English version is available at this time. Koei does translate some of its older games to English. Hopefully this one will get translated. Check out the Official Site for more screenshots.

I do not study Japanese history but I can imagine that the situation during the sengokujidai is messier then the one depicted in STW. A country the size of Japan can have any number of warlords. Its a nice touch that these minor factions are playable, such that you get to experience the feeling of being a small fry in a pond with big fishes like Oda and Hojo

Im currently playing the buddhist faction, just found out that its read honganji. Hard going with just 2 cities but fun Here are screenshots of the Zoomed in map and the battle screen.

There are many cool features, as far as I can make out in 2 hours of testing. For one thing you get to pay another allied faction to launch a joint attack on an enemy. There are also vessel factions. I'm not sure how it works yet..whether you get tribute or anything, but when I asked my vessel to join me for a joint attack they came promptly enough. Now if only I can get powerful enough to make vessels of Oda

At first glance, the battle seems more simplistic, compared to STW. Its in 2D and have a more cartoonish feel. The graphics are attractive enough though.