Where is that switch or watever to lower the bridge of Shurugeon Castle? While I was at the castle doing the D'Soto quest I never came across anything to lower the bridge and now I get this ninja quest. Is the trigger activated after the ninja quest comes on?

Go to where the drawbridge is at the front of the castle. Now you go to the tower on your right. There is a lever at the top of the stairs. Be sure not to kill ANYTHING while you are on the quest, or else you will have to redo it again. Run there, flip the switch, and run back. If you haven't killed the Amazoni Mantraps yet, I suggest killing them first.

Have a good look around the towers on eiter side of the drawbridge. Kill the sentry wraith the switch is behind him.

I'm intrigued. The quest says that you shouldn't disturb anything before lowering the drawbridge and a number of people have repeated that in the forum - but I killed everything i met, pulled the lever, and got promoted, no problem. Did anyone get refused the promotion because they distubed the denizens of the castle in the process? Just wondering.

Perhaps it means that your Ninja cannot kill anything...which could break down as not hit at all or just not have the killing blow in a battle. The latter could be quite possible if you have a warlock blasting everything in sight with spells.

I killed the silent sentry (not sure who dealt the final blow) then flipped the switch, went back to town but Master Wu still says I didn't complete the quest.
I went back to the castle and the drawbridge had been raised again. This time I just flipped the switch without attacking the sentry but I got stuck on the drawbridge (graphic bug) and had to shut down.

I went there are killed everything that was in the castle zip code, and was turned down flat by Master Wu. I then ran like a madman dodging everything, I then received the promotion.

I think ol' Rumblebelly's got this one nailed down. (Regis )

Seems that you can kill whatever you want while you're doing the quest, but if your ninja-in-training lands a killing blow on anything, no sushi for him (no shurugi either).

I had a different experience alltogether. By the time my rat was high enough to be a ninja I had already finished the castle, lowered the bridge, and killed EVERYTHING that moved inside. It promoted me for finishing the quest, and I didn't even have to leave the dojo to do it.