Koei has just released the newest Nobunaga's Ambition: http://www.nobunagasambition.eu/
It's a strategy game set in the Sengoku jidai. Pick a starting date, choose a daimyou, develop your clan, conduct diplomacy, gain Imperial offices and wage war against your enemies.
There are hundreds of officers and you can even create your own ones with the editor. Dozens of events will allow you to replay history if you choose to do so.
The map is huge and features lots of historically correct provinces, clans, castles and fortifications.
Warfare is rather simple as there is only one troop type: a mixed formation that can be improved by equipping them with horses and arquebuses. Troop leaders usually have some kind of special attack to improve your men or to weaken the enemy.
Looks like a worthy competitor to Shougun II.