What is this ????????!!!!!

[caravel]

Welcome buddha95

What triggered it: A faction heir that had not yet come of age when his faction was wiped out, siezed the opportunity due to you having a province or provinces that had loyalty under 120%.

How often will it happen: Not often, but it will most likely occur when the above conditions are met.

Can it be avoided: Yes, you can avoid it by changing the taxrate and keeping provincial loyalty as high as possible. Hold down shift often and look for any provinces that aren't green. Place Shinobi in your provinces. I find three per province is usually enough, but start out with at least one per province and work from there. They will gain honour, and thus effectiveness, as they catch rival Ninja/Shinobi. Also certain buildings increast loyalty in your provinces i.e. border forts and watchtowers. Buddhist temples and, IIRC the the Tea House also improve loyalty. Upgrading the Tea House also enables you to train Shinobi of a higher honour.