Romance of the Three Kingdoms IX in the Strategy genre.
It's available on Steam if you want to play it! It's ¥3,080, which is a bit pricey given its age and it's Japanese/Chinese only without a translation patch (although you've lived in Japan long enough that it should be ok!). Koei-Tecmo went through a period a couple years back where they released a couple of old games on Steam every month. A lot of the old ROTK and Nobunaga games are on there now.
I'll have to give it a try some day. Never played 9. It didn't release in Europe unfortunately so I've not had the chance before. 8 was still our newest one while Japan and the US were on 10 already! 8 was fantastic though, and our next one was 11 which was also great!