You and whose army?

[Tora]

Playing 1580/Shimazu/hard, I noticed that Oda only had Wakasa so I offered an alliance as he had no friends and hopefully would leave everything to me after his very imminent demise.
He replied something like that any hint of treachery on my part would result in the unleashing of his mighty and numerous force, but yes....alright then.
His total forces numbered a breathtaking 368.

[KumaRatta Yamamoto]

I have noticed that AI clan's seem to have a different view of alliances depending in what year you start your campaign. In 1530, the AI clan's seem more honorable and keep the alliance. In 1580, don't count on it alliances mean nothing, In one of my first campaigns starting in 1580, i was attacked by my two first "allies" before any other clan

I also like the fact that in 1580, three clan are christians.

[Khan7]

I don't think the differnce is hardwired, as the only variables I am aware of are whether the clan in question is lesser than, greater than, or superior to you, whether they share your religion, and what your geographical and tactical/strategic relationship is.

So any differnces in clan behavior that you may have noticed between, for instance, SJ 1530 and SJ 1580 is almost certainly due to those mentioned factors.

Matt