I recently started playing Shogun 2 again after a very long time away. I decided to play the standard Shogun 2 campaign as the Hattori. I managed to make my way up the civic tree to be able to recruit my special unit - the Hattori Kishu ninja. Even in vanilla back in the day, I had no idea how to use these units properly. They seemed pointless and a waste of upkeep. The AI either always seem to find them (especially in large open terrain combat), or the stealth ability was not nearly long enough for me to be able to effectively use them to assassinate anyone during sieges.
Advice is welcome, but videos of effective use would be even better. I already looked on the intertubes, but much of the advice anyway is outside of darthmod. I decided to ask here since darth might have changed their values anyway (no idea).