Being one to always try and get the most out of my gaming experience I never shirk away from the dark side ;-)...
Here is the latest underhanded strategy I undertook..
Playing as Mori Legendary I had taken the province belonging to Kittatawa? while they were out of the castle..They had 2 huge stacks of teched samurai I did not have the numbers to defeat so as an exploit I made them a vassal..thus gaining time to deal with them later instead of having to fight them as rebels anyway..
Well I convinced them then to go to war with my enemies, luckily more me they were an expansive lot and liked to march to war, therefore I was also able to use them often as fodder before taking provinces out from under them..still leaving them with just the one province and their armies no where near it..
The real exploit here though is every-time my diplomatic relations get so poor with them that I feel they will go to war I simply retake their Provence and make them vassals all over again..Ta-da! sudden 100 to military alliance no territorial expansion minuses and they welcome me as their honourable friend!!! ;-)