Dynasty Warriors 7

I just want to clarify that you do NOT have to do this at Hu lao gate and it can easily be done in a mission of the story mode that requires it such as the battle where you flood his castle (Xia Pi) which is in the Wei and Shu story lines ( Thanks DrCanadianNinja ). And of course, this would be easiest done on easy mode or beginner as on normal Lu Bu is capable of annihilating you in a single combo if he wanted to. You may be able to pop this in conquest mode easier but I haven't tested that as I unlocked the achievement playing story and can't test it now but if you try it I would be glad to update my guide to include it if you want to leave a comment saying it's possible.

Simple as anything. The battle of XiaPi (Cao Cao & Liu Bei vs. Lu Bu) is you're best bet. He isn't hard to kill and you don't even need to have it on any higher than Beginner difficulty if you have a hard time killing him. Also, he's the main enemy commander so you NEED to kill him to win the fight. Easy. Have fun :)

This is easily achievable on even normal mode of any of the main 3's story mode. If absolutely want to get this on Hu Lao Gate or on the Escape from Dong Zhuo mission (Wei's story), then the best way to achieve this is to just musou the crap out of him. If you're lucky enough to get into the red without dying, stay away from him until you get full musou, then turn around and smack him in the face with it... run away, rinse and repeat. In Hu Lao (not on Escape from Dong Zhuo), Lu Bu may run away from the battle after awhile. If you can get lucky, this is also a good time to get the last few hits on him, but this could also ruin it for you if he manages to escape.

By and large though, the easiest place to achieve this on is Xia Pi since he doesn't sponge your hits and actually flinches (although be wary if you kill Diao Chan as he'll get 2x strength, defense, and speed).

one of the hardest achivments on the game.

i unlocked this achievment on hu lao gate.

to make it easier dont attck him on your own make sure you have allies with you cause they will attack him as well so he wont focus on you. also use your musou as much as possible to make it easier.