Surprisingly entertaining and substantially less complicated than I thought it would be, CRUSADER KINGS II: JAPAN EDITION (Sengoku) is a RTS game that puts you in charge of uniting the clans of Japan under your rule as Shogun. Of course, there's nearly a hundred other different clans with that very same objective, so you'll have to play your cards right using diplomacy, might and sabotage to earn the respect of the emperor and conquer the nation.
You can HIRE NINJAS to COUNTER OTHER NINJAS, assemble armies of RONIN and even stab other leaders in the back! Also, GUNS. IF you happen to be visited by western traders.
Also, since it's Ancient Japan we're talking about, HONOR is a very important currency, with a decisive hand in negociations and your internal political stability: be an honored leader and the other clans and your people will respect you and your decisions. Screw up and you might as well commit sepukku to guarantee your lineage (yes, you can do that and, yes, if your son fails to become the next ruler when you die, it's GG).
RECOMMEND. Just beware that matches can (and wil) last FOREVER (as in, more than half a dozen hours forever), so you better be patient. Also, do yourself a favor and play at maximum speed - you can pause to issue orders anyway.